Document and Entity Information - shares	9 Months Ended
Document and Entity Information - shares	Sep. 30, 2018	Nov. 01, 2018
Document And Entity Information [Abstract]
Entity Registrant Name	Sientra, Inc.
Entity Central Index Key	0001551693
Document Type	10-Q
Document Period End Date	Sep. 30, 2018
Amendment Flag	false
Current Fiscal Year End Date	--12-31
Entity Filer Category	Accelerated Filer
Entity Small Business	false
Entity Emerging Growth Company	true
Entity Ex Transition Period	true
Entity Common Stock, Shares Outstanding		28,599,319
Document Fiscal Year Focus	2018
Document Fiscal Period Focus	Q3
Trading Symbol	SIEN

Condensed Consolidated Balance Sheets - USD ($) $ in Thousands	Sep. 30, 2018	Dec. 31, 2017
Current assets:
Cash and cash equivalents	$ 103,008	$ 26,588
Accounts receivable, net of allowances of $1,384 and $4,816 at September 30, 2018 and December 31, 2017, respectively	18,956	6,569
Inventories, net	22,909	20,896
Prepaid expenses and other current assets	3,482	1,512
Total current assets	148,355	55,565
Property and equipment, net	2,440	4,763
Goodwill	12,507	12,507
Other intangible assets, net	17,069	18,803
Other assets	709	575
Total assets	181,080	92,213
Current liabilities:
Current portion of long-term debt	3,356	24,639
Accounts payable	11,510	5,811
Accrued and other current liabilities	25,218	13,474
Legal settlement payable	410	1,000
Customer deposits	7,706	5,423
Sales return liability	5,335
Total current liabilities	53,535	50,347
Long-term debt	31,361
Deferred and contingent consideration	6,330	12,597
Warranty reserve and other long-term liabilities	1,877	1,646
Total liabilities	93,103	64,590
Commitments and contingencies (Note 14)
Stockholders’ equity:
Preferred stock, $0.01 par value – Authorized 10,000,000 shares; none issued or outstanding
Common stock, $0.01 par value — Authorized 200,000,000 shares; issued 28,650,944 and 19,474,702 and outstanding 28,578,217 and 19,401,975 shares at September 30, 2018 and December 31, 2017 respectively	286	194
Additional paid-in capital	425,417	307,159
Treasury stock, at cost (72,727 shares at September 30, 2018 and December 31, 2017)	(260)	(260)
Accumulated deficit	(337,466)	(279,470)
Total stockholders’ equity	87,977	27,623
Total liabilities and stockholders’ equity	$ 181,080	$ 92,213

Condensed Consolidated Balance Sheets (Parenthetical) - USD ($) $ in Thousands	Sep. 30, 2018	Dec. 31, 2017
Statement Of Financial Position [Abstract]
Accounts receivable, allowances (in dollars)	$ 1,384	$ 4,816
Preferred stock, par value (in dollars per share)	$ 0.01	$ 0.01
Preferred stock, shares authorized	10,000,000	10,000,000
Preferred stock, shares issued	0	0
Preferred stock, shares outstanding	0	0
Common stock, par value (in dollars per share)	$ 0.01	$ 0.01
Common stock, shares authorized	200,000,000	200,000,000
Common stock, shares issued	28,650,944	19,474,702
Common stock, shares outstanding	28,578,217	19,401,975
Treasury stock, shares	72,727	72,727

Condensed Consolidated Statements of Operations - USD ($)	3 Months Ended		9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
Income Statement [Abstract]
Net sales	$ 16,875,000	$ 9,819,000	$ 49,104,000	$ 25,477,000
Cost of goods sold	6,398,000	3,484,000	19,154,000	8,427,000
Gross profit	10,477,000	6,335,000	29,950,000	17,050,000
Operating expenses:
Sales and marketing	15,254,000	7,981,000	45,990,000	21,100,000
Research and development	2,881,000	2,911,000	7,930,000	7,677,000
General and administrative	11,904,000	9,298,000	31,419,000	23,753,000
Legal settlement				10,000,000
Total operating expenses	30,039,000	20,190,000	85,339,000	62,530,000
Loss from operations	(19,562,000)	(13,855,000)	(55,389,000)	(45,480,000)
Other income (expense), net:
Interest income	133,000	54,000	214,000	112,000
Interest expense	(953,000)	(409,000)	(2,474,000)	(603,000)
Other income (expense), net	(163,000)	(155,000)	(347,000)	(151,000)
Total other income (expense), net	(983,000)	(510,000)	(2,607,000)	(642,000)
Loss before income taxes	(20,545,000)	(14,365,000)	(57,996,000)	(46,122,000)
Income tax expense	0	16,000	0	70,000
Net loss	$ (20,545,000)	$ (14,381,000)	$ (57,996,000)	$ (46,192,000)
Basic and diluted net loss per share attributable to common stockholders	$ (0.72)	$ (0.74)	$ (2.39)	$ (2.42)
Weighted average outstanding common shares used for net loss per share attributable to common stockholders:
Basic and diluted	28,462,975	19,328,244	24,312,300	19,079,788

Condensed Consolidated Statements of Cash Flows - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017
Cash flows from operating activities:
Net loss	$ (57,996)	$ (46,192)
Adjustments to reconcile net loss to net cash used in operating activities:
Depreciation and amortization	2,500	2,037
Provision for doubtful accounts	996	84
Provision for warranties	2	133
Provision for inventory	708	468
Amortization of acquired inventory step-up	106	802
Change in fair value of warrants	333	151
Change in fair value of deferred consideration	18	(10)
Change in fair value of contingent consideration	2,178	768
Change in deferred revenue	275
Non-cash portion of debt extinguishment loss		16
Amortization of debt discount and issuance costs	132	97
Non-cash interest expense		1
Stock-based compensation expense	10,077	4,777
Loss on disposal of property and equipment		12
Deferred income taxes		70
Changes in assets and liabilities, net of effects from acquisitions:
Accounts receivable	(9,476)	411
Inventories	(2,827)	1,208
Prepaid expenses, other current assets and other assets	(2,168)	(2,083)
Insurance recovery receivable	33	9,300
Accounts payable	6,780	(478)
Accrued and other liabilities	3,789	3,613
Legal settlement payable	(590)	(9,900)
Customer deposits	2,283	(987)
Sales return liability	1,429
Net cash used in operating activities	(41,418)	(35,702)
Cash flows from investing activities:
Purchase of property and equipment	(414)	(1,173)
Business acquisitions, net of cash acquired		(18,455)
Net cash used in investing activities	(414)	(19,628)
Cash flows from financing activities:
Proceeds from exercise of stock options	1,149	1,327
Proceeds from issuance of common stock under ESPP	993	647
Tax payments related to shares withheld for vested restricted stock units (RSUs)	(1,419)	(569)
Net proceeds from issuance of common stock	107,551
Gross borrowings under the Term Loan	10,000	25,000
Gross borrowings under the Revolving Loan	12,109	5,000
Repayment of the Revolving Loan	(12,109)	(5,000)
Deferred financing costs	(22)	(646)
Net cash provided by financing activities	118,252	25,759
Net increase (decrease) in cash and cash equivalents	76,420	(29,571)
Cash and cash equivalents at:
Beginning of period	26,588	67,212
End of period	103,008	37,641
Supplemental disclosure of cash flow information:
Interest paid	2,526	305
Supplemental disclosure of non-cash investing and financing activities:
Property and equipment in accounts payable and accrued liabilities	1,900	700
Acquisition of business, deferred and contingent consideration obligations at fair value		10,192
Non-cash deferred consideration settlement	1,000
Non-cash settlement of assets held for sale in accounts payable	$ 2,674
Forgiveness of SVB Loan commitment fee		$ 750

Formation and Business of the Company

9 Months Ended

Sep. 30, 2018

Organization Consolidation And Presentation Of Financial Statements [Abstract]

Formation and Business of the Company

1.	Formation and Business of the Company

a.

Formation

Sientra, Inc. (“Sientra”, the “Company,” “we,” “our” or “us”), was incorporated in the State of Delaware on August 29, 2003 under the name Juliet Medical, Inc. and subsequently changed its name to Sientra, Inc. in April 2007. The Company acquired substantially all the assets of Silimed, Inc. on April 4, 2007. The purpose of the acquisition was to acquire the rights to the silicone breast implant clinical trials, related product specifications and pre-market approval, or PMA, assets. Following this acquisition, the Company focused on completing the clinical trials to gain FDA approval to offer its silicone gel breast implants in the United States.

In March 2012, the Company announced it had received approval from the FDA for its portfolio of silicone gel breast implants, and in the second quarter of 2012 the Company began commercialization efforts to sell its products in the United States. The Company, based in Santa Barbara, California, is a medical aesthetics company that focuses on serving board-certified plastic surgeons and offers a portfolio of silicone shaped and round breast implants, scar management, tissue expanders, and body contouring products.

In November 2014, the Company completed an initial public offering, or IPO, and its common stock is listed on the Nasdaq Stock Exchange under the symbol “SIEN.”

b.

Acquisition of miraDry

On June 11, 2017, Sientra entered into an Agreement and Plan of Merger, or the Merger Agreement, with miraDry, (formerly Miramar Labs), pursuant to which Sientra commenced a tender offer to purchase all of the outstanding shares of miraDry’s common stock for (i) $0.3149 per share, plus (ii) the contractual right to receive one or more contingent payments upon the achievement of certain future sales milestones. The total merger consideration was $18.7 million in upfront cash and the contractual rights represent potential contingent payments of up to $14 million. The transaction, which closed on July 25, 2017, added the miraDry System to Sientra’s aesthetics portfolio.

c.

Regulatory Review of Vesta Manufacturing

The Company has engaged Vesta Intermediate Funding, Inc., or Vesta, a Lubrizol Lifesciences company, for the manufacture and supply of the Company’s breast implants. On March 14, 2017, the Company announced it had submitted a site-change pre-market approval, or PMA supplement, to the FDA for the manufacture of the Company’s PMA-approved breast implants at the Vesta manufacturing facility. On January 30, 2018, the Company announced the FDA has granted approval of the site-change pre-market approval, or PMA, supplement for the Company’s contract manufacturer, Vesta, to manufacture its silicone gel breast implants. In support of the move to the Vesta manufacturing facility, the Company also implemented new manufacturing process improvements which, in consultation with the FDA, required three (3) additional PMA submissions. In addition to approving the manufacturing site-change supplement, the FDA has approved our three (3) process enhancement submissions on January 10, 2018, January 19, 2018 and April 17, 2018.

d.

Follow-On Offering

On May 7, 2018, the Company completed an underwritten follow-on public offering of 7,407,408 shares of its common stock at $13.50 per share, as well as 1,111,111 additional shares of its common stock pursuant to the full exercise of the over-allotment option granted to the underwriters. Net proceeds to the Company were approximately $107.6 million after deducting underwriting discounts and commissions of $6.9 million and offering expenses of approximately $0.5 million.

Summary of Significant Accounting Policies

9 Months Ended

Sep. 30, 2018

Accounting Policies [Abstract]

Summary of Significant Accounting Policies

2.	Summary of Significant Accounting Policies

a.

Basis of Presentation

The accompanying unaudited condensed consolidated financial statements in this Quarterly Report on Form 10-Q have been prepared in accordance with accounting principles generally accepted in the United States of America, or GAAP, and the rules and regulations of the U.S. Securities and Exchange Commission, or SEC. Accordingly, they do not include certain footnotes and financial presentations normally required under accounting principles generally accepted in the United States of America for complete financial reporting. The interim financial information is unaudited, but reflects all normal adjustments and accruals which are, in the opinion of management, considered necessary to provide a fair presentation for the interim periods presented. The accompanying condensed consolidated financial statements should be read in conjunction with the Company’s audited consolidated financial statements and notes thereto included in the Company’s Annual Report on Form 10-K for the year ended December 31, 2017 filed with the SEC on March 13, 2018 and Form 10-K/A filed on April 30, 2018, or the Annual Report. The results for the three and nine months ended September 30, 2018 are not necessarily indicative of results to be expected for the year ending December 31, 2018, any other interim periods, or any future year or period.

b.

Liquidity

Since the Company’s inception, it has incurred significant net operating losses and the Company anticipates that losses will continue in the near term. The Company expects its operating expenses will continue to grow as they expand operations. The Company will need to generate significant net sales to achieve profitability. To date, the Company has funded operations primarily with proceeds from the sales of preferred stock, borrowings under term loans, sales of products since 2012, and the proceeds from the sale of common stock in public offerings.

The accompanying condensed consolidated financial statements have been prepared on a going concern basis, which implies the Company will continue to realize its assets and discharge its liabilities in the normal course of business. As of September 30, 2018, the Company had cash and cash equivalents of $103.0 million. Since inception, the Company has incurred recurring losses from operations and cash outflows from operating activities. The continuation of the Company as a going concern is dependent upon many factors including liquidity and the ability to raise capital. The Company received FDA approval of their PMA supplement on April 17, 2018 and was then able to access a $10.0 million term loan pursuant to an amendment to the credit agreement with MidCap Financial Trust, or MidCap. In addition, in February 2018, the Company entered into an At-The-Market Equity Offering Sales Agreement with Stifel, Nicolaus & Company, Incorporated, or Stifel, as sales agent pursuant to which the Company may sell, from time to time, through Stifel, shares of our common stock having an aggregate gross offering price of up to $50.0 million. As of September 30, 2018, the Company has not sold any common stock pursuant to the sales agreement. Further, on May 7, 2018, the Company completed a public offering of its common stock, raising approximately $107.6 million in net proceeds after deducting underwriting discounts and commissions and other offering expenses.

The Company believes that its cash and cash equivalents will be sufficient to fund its operations for at least the next 12 months. To fund ongoing operating and capital needs, the Company may need to raise additional capital in the future through the sale of equity securities and incremental debt financing.

c.

Use of Estimates

The preparation of the condensed consolidated financial statements, in conformity with GAAP, requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities and disclosure of contingent assets and liabilities at the date of the condensed consolidated financial statements and the reported amounts of revenues and expenses during the reporting periods. Actual results could differ from those estimates.

d.

Significant Accounting Policies

Revenue Recognition

The Company recognizes revenue when the Company transfers control of promised goods or services to customers in an amount that reflects the consideration to which the Company expects to be entitled to in exchange for those goods or services. See Note 3 - Revenue for further discussion.

There have been no other changes to the accounting policies during the three and nine months ended September 30, 2018, as compared to the significant accounting policies described in the “Notes to Financial Statements” in the Annual Report.

e.

Recent Accounting Pronouncements

Recently Adopted Accounting Standards

In June 2018, the FASB issued ASU 2018-07, Compensation - Stock Compensation (Topic 718), to simplify the accounting for non-employee share-based payment transactions by expanding the scope of ASC Topic 718 to include share-based payment transactions for acquiring goods and services from non-employees. Under the new standard, most of the guidance on stock compensation payments to non-employees would be aligned with the requirements for share-based payments granted to employees. ASU 2018-07 supersedes Subtopic 505-50, Equity—Equity-Based Payments to Non-Employees, and is effective for all public entities for fiscal years beginning after December 15, 2018, and interim periods within those fiscal years. Early adoption is permitted, but no earlier than a company’s adoption date of Topic 606, Revenue from Contracts with Customers. The Company early adopted ASU 2018-07 in the third quarter of 2018 and there was no material impact on its consolidated financial statements from the adoption.

In May 2014, the FASB issued ASU 2014-09, Revenue from Contracts with Customers (Topic 606). Topic 606 supersedes the revenue recognition requirements in Topic 605 Revenue Recognition (Topic 605) and requires entities to recognize revenue when control of the promised goods or services is transferred to customers at an amount that reflects the consideration to which the entity expects to be entitled to in exchange for those goods or services. The Company adopted Topic 606 in the first quarter of 2018 to all contracts using the modified retrospective method. The adoption of Topic 606 did not have a material impact on the Company’s historical net losses and, therefore, no adjustment was made to the opening balance of retained earnings. The comparative information has not been restated and continues to be reported under the accounting standards in effect for those periods.

In accordance with Topic 606 disclosure requirements, the impact of adoption on the Company’s condensed consolidated balance sheet was as follows (in thousands):



	As Reported		Total		Adjusted
	December 31, 2017		Adjustment		January 1, 2018
Balance Sheet
Assets
Accounts receivable, net of allowances	$	6,569		3,906		10,475
Liabilities
Sales return liability	$	—		3,906		3,906



	As Reported		Total			Amounts Under
	September 30, 2018		Adjustment			Previous Standards
Balance Sheet
Assets
Accounts receivable, net of allowances	$	18,956		(5,335	)		13,621
Liabilities
Sales return liability	$	5,335		(5,335	)		—

Additionally, in accordance with Topic 606, the balance of breast product inventory estimated to be returned as of September 30, 2018 is included in the components of the Company’s inventory as “finished goods – right of return” in Note 9b - Inventories. Prior to the adoption of Topic 606, the inventory impact of estimated returns for breast products was included in the “finished goods” inventory balance and was not separately disclosed.

The adoption of Topic 606 did not have a material impact on the Company’s condensed consolidated statement of operations.

In August 2016, the FASB issued ASU 2016-15, Statement of Cash Flows – Classifications of Certain Cash Receipts and Cash Payments (Topic 230). The standard update addresses eight specific cash flow issues not currently addressed by GAAP, with the objective of reducing the existing diversity in practice of how these cash receipts and payments are presented and classified in the statement of cash flows. The ASU requires a retrospective approach to adoption. The Company adopted the ASU in the first quarter of 2018. The adoption of this ASU did not have a material impact on the Company’s condensed consolidated financial statements.

In January 2017, the FASB issued ASU 2017-01, Business Combinations (Topic 805) - Clarifying the Definition of a Business. The standard adds guidance to assist entities with evaluating whether transactions should be accounted for as acquisitions (or disposals) of assets or businesses by providing a more specific definition of a business. The Company adopted the ASU in the first quarter of 2018 on a prospective basis. The adoption of this ASU did not have a material impact on the Company’s condensed consolidated financial statements.

In May 2017, the FASB issued ASU 2017-09, Compensation—Stock Compensation (Topic 718): Scope of Modification Accounting. The standard provides clarification on when modification accounting should be used for changes to the terms or conditions of a share-based payment award to which an entity would be required to apply modification accounting under Accounting Standard Codification, or ASC, 718. The Company adopted the ASU in the first quarter of 2018 on a prospective basis. The adoption of this ASU did not have a material impact on the Company’s condensed consolidated financial statements.

Recently Issued Accounting Standards

In February 2016, the FASB issued ASU 2016-02, Leases (Topic 842) which supersedes FASB Accounting Standard Codification Leases (Topic 840). The standard is intended to increase the transparency and comparability among organizations by recognizing lease assets and lease liabilities on the balance sheet and disclosing key information about leasing arrangements. This accounting standard update will be effective for the Company beginning in fiscal year 2019. In July 2018, the FASB issued ASU 2018-11, Leases (Topic 842): Targeted Improvements, which, among other things, allows companies to elect an optional transition method to apply the new lease standard through a cumulative-effect adjustment in the period of adoption. The Company is currently evaluating the impact that adoption of these standards will have on the financial statements and related disclosures.

In February 2018, the FASB issued ASU 2018-02, Income Taxes (Topic 740), which allows for an entity to elect to reclassify the income tax effects on items within accumulated other comprehensive income resulting from U.S. Tax Cuts and Jobs Act to retained earnings. The guidance is effective for fiscal years beginning after December 15, 2018 with early adoption permitted, including interim periods within those years. The Company does not expect to elect to reclassify the income tax effects under ASU 2018-05, as it does not have a material impact on the condensed consolidated financial statements.

In August 2018, the FASB issued ASU 2018-13, Fair Value Measurement (Topic 820) - Disclosure Framework - Changes to the Disclosure Requirements for Fair Value Measurement. The amendment modifies, removes, and adds certain disclosure requirements on fair value measurements. The ASU is effective for annual periods, including interim periods within those annual periods, beginning after December 15, 2019. The amendments on changes in unrealized gains and losses, the range and weighted average of significant unobservable inputs used to develop Level 3 fair value measurements, and the narrative description of measurement uncertainty should be applied prospectively for only the most recent interim or annual period presented in the initial fiscal year of adoption. All other amendments should be applied retrospectively to all periods presented upon their effective date. Early adoption is permitted. The Company is currently evaluating the impact adoption of the standard on the consolidated financial statements.

In August 2018, the FASB issued ASU 2018-15, Intangibles - Goodwill and Other - Internal-Use Software (Subtopic 350-40) - Customer’s Accounting for Implementation Costs Incurred in a Cloud Computing Arrangement that is a Service Contract. The amendment aligns the requirements for capitalizing implementation costs incurred in a hosting arrangement that is a service contract with the requirements for capitalizing implementation costs incurred to develop or obtain internal-use software (and hosting arrangements that include an internal use software license). The accounting for the service element of a hosting arrangement that is a service contract is not affected by the amendment. The ASU is effective for annual periods, including interim periods within those annual periods, beginning after December 15, 2019. Early adoption is permitted. The Company is currently evaluating the impact of adoption of the standard on the consolidated financial statements.

f.Reclassifications

Certain reclassifications have been made to prior year amounts to conform to the current year presentation.

Revenue

9 Months Ended

Sep. 30, 2018

Revenue From Contract With Customer [Abstract]

Revenue

3.

Revenue

Revenue Recognition

The Company generates revenue primarily through the sale and delivery of promised goods or services to customers and recognizes revenue when control is transferred to customers, in an amount that reflects the consideration the Company expects to be entitled to in exchange for the goods or services. Sales prices are documented in the executed sales contract or purchase order prior to the transfer of control to the customer. Customers may enter into a separate extended service agreement to purchase an extended warranty for miraDry products from the Company whereby the payment is due at the inception of the agreement. Revenue for extended service agreements are recognized ratably over the term of the agreements.

The Company introduced its Platinum20 Limited Warranty Program, or Platinum20, in May 2018 on all OPUS breast implants implanted in the United States or Puerto Rico on or after May 1, 2018. Platinum20 provides for financial assistance for revision surgeries and no-charge contralateral replacement implants upon the occurrence of certain qualifying events. The Company considers Platinum20 to have an assurance warranty component and a service warranty component. The assurance component is recorded as a warranty liability at the time of sale (as discussed in Note 7). The Company considers the service warranty component as an additional performance obligation and defers revenue at the time of sale by estimating a standalone selling price using the expected cost plus margin approach for each performance obligation. The Company recognizes the revenue once all performance obligations have been met. The liability for the service warranty as of September 30, 2018 was $0.2 million, of which $0.1 million is considered a short-term obligation and is included in “accrued and other current liabilities” and $0.1 million is considered a long-term obligation and is included in “warranty reserve and other long-term liabilities” on the condensed consolidated balance sheet. The performance obligation is satisfied at the time that Platinum20 benefits are provided and are expected to be satisfied over the following two years for financial assistance and 20 years for product replacement. Revenue recognized for the service warranty performance obligations for the three and nine months ended September 30, 2018 was immaterial.

The Company also leverages a distributor network for selling the miraDry System internationally. The Company recognizes revenue when control of the goods or services is transferred to the distributors. Standard terms in these agreements do not allow for trial periods, right of return, refunds, rebates, payment contingent on obtaining financing or other terms that could impact the customer’s payment obligation. Contract liabilities are included in “accrued and other current liabilities” in the condensed consolidated balance sheet.

A portion of the Company’s revenue is generated from the sale of consigned inventory of breast implants maintained at doctor, hospital, and clinic locations. For these products, revenue is recognized at the time the Company is notified by the customer that the product has been implanted, not when the consigned products are delivered to the customer’s location.

For Breast Products, with the exception of the Company’s BIOCORNEUM scar management products, the Company allows for the return of products from customers within six months after the original sale, which is accounted for as variable consideration. Reserves are established for anticipated sales returns based on the expected amount calculated with historical experience, recent gross sales and any notification of pending returns. The estimated sales return is recorded as a reduction of revenue and as a sales return liability in the same period revenue is recognized. Actual sales returns in any future period are inherently uncertain and thus may differ from the estimates. If actual sales returns differ significantly from the estimates, an adjustment to revenue in the current or subsequent period would be recorded. The Company has established an allowance for sales returns of $5.3 million and $3.9 million as of September 30, 2018 and December 31, 2017, respectively, recorded as “sales return liability” on the condensed consolidated balance sheet under Topic 606 as of September 30, 2018 and recorded in “accounts receivable, net of allowances,” at December 31, 2017 on the condensed consolidated balance sheet, as indicated above in “Recently Adopted Accounting Standards.”

Sales tax, value-added tax, and other taxes the Company may collect concurrent with revenue-producing activities are excluded from the measurement of the transaction price and thus from revenue.

Arrangements with Multiple Performance Obligations

The Company has determined that the delivery of each unit of product in the Company’s revenue contracts with customers is a separate performance obligation. The Company’s revenue contracts may include multiple products or services, each of which is considered a separate performance obligation. For such arrangements, the Company allocates revenue to each performance obligation based on its relative standalone selling price. The Company generally determines standalone selling prices based on observable prices or using an expected cost plus margin approach when an observable price is not available. The Company invoices customers once products are shipped or delivered to customers depending on the negotiated shipping terms.

The Company defers the value of the service warranty revenue and recognizes it once all performance obligations have been met.

Practical Expedients and Policy Election

The Company generally expenses sales commissions when incurred because the amortization period would have been one year or less. These costs are recorded within sales and marketing expenses.

The Company does not adjust accounts receivable for the effects of any significant financing components as customer payment terms are shorter than one year.

The Company has elected to account for shipping and handling activities performed after a customer obtains control of the products as activities to fulfill the promise to transfer the products to the customer. Shipping and handling activities are largely provided to customers free of charge for the Breast Products segment. The associated costs were $0.9 million and $0.7 million for the nine months ended September 30, 2018 and 2017. The associated costs were $0.3 million and $0.2 million for the three months ended September 30, 2018 and 2017. These costs are viewed as part of the Company’s marketing programs and are recorded as a component of sales and marketing expense in the condensed consolidated statement of operations as an accounting policy election. For the miraDry segment, shipping and handling charges are typically billed to customers and recorded as revenue. The shipping and handling costs incurred are recorded as a component of cost of goods sold in the condensed consolidated statement of operations. The associated costs were $0.1 million and $0.2 million for the three and nine months ended September 30, 2018, respectively.

Acquisitions

9 Months Ended

Sep. 30, 2018

Business Combinations [Abstract]

Acquisitions

4.	Acquisitions

a.

Acquisition of miraDry

On June 11, 2017, Sientra entered into the Merger Agreement with miraDry, pursuant to which Sientra commenced a tender offer to purchase all of the outstanding shares of miraDry’s common stock for (i) $0.3149 per share, plus (ii) the contractual right to receive one or more contingent payments upon the achievement of certain future sales milestones. The total merger consideration was $18.7 million in upfront cash and the contractual rights represent potential contingent payments of up to $14.0 million. The transaction, which closed on July 25, 2017, or the Acquisition Date, added the miraDry System, the only FDA cleared device indicated to reduce underarm sweat, odor and hair of all colors, to Sientra’s aesthetics portfolio. The Company did not record any professional fees related to the acquisition for the three and nine months ended September 30, 2018. The Company recorded $2.6 million and $3.0 million in professional fees related to the acquisition for the three and nine months ended September 30, 2017. The aggregate acquisition date fair value of the consideration transferred was approximately $29.6 million, consisting of the following (in thousands):

	Fair Value
Cash consideration at Acquisition Date (other than debt payoff)	$	6,193
Cash consideration at Acquisition Date (debt payoff)		12,467
Deferred consideration		966
Contingent consideration		9,946
Total purchase consideration	$	29,572

The Company funded the cash consideration, including the debt payoff amount with cash on hand. The cash consideration included the payoff of miraDry’s existing term loan, or the Note Purchase Agreement dated January 27, 2017 and bridge loan, or the January 2017 Bridge Loan, including interest. The deferred consideration related to cash held back to be used for either potential litigation-related expenses or for payments to certain former investors of miraDry, as defined in the Note Purchase Agreement dated January 27, 2017, one year following the Acquisition Date. Upon reaching one year, the deferred consideration has been classified as $0.4 million of legal settlement payable in the condensed consolidated balance sheet and $0.6 million has offset legal fees paid that the Company had previously included in “prepaid expenses and other current assets” on the condensed consolidated balance sheet. Contingent consideration of future cash payments of a maximum of $14.0 million represents the contractual right of certain former miraDry shareholders to receive one or more contingent payments upon achievement of certain future sales milestones and includes certain amounts due to investors related to the remaining balances on the January 2017 Bridge Note and accrued royalty obligations, with certain amounts held back for potential litigation-related expenses. The fair value of the contingent consideration at the acquisition date was determined using a Monte-Carlo simulation model. The inputs include the estimated amount and timing of future net sales, and a risk-adjusted discount rate. The inputs are significant inputs not observable in the market, which are referred to as Level 3 inputs and are further discussed in Note 6. The contingent consideration component is subject to the recognition of subsequent changes in fair value through general and administrative expense in the condensed consolidated statement of operations.

In accordance with ASC 805, the Company has recorded the acquired assets (including identifiable intangible assets) and liabilities assumed at their respective fair value. The allocation of the total purchase price is as follows (in thousands):

	July 25,
	2017
Cash	$	205
Accounts receivable, net		2,091
Inventories, net		7,064
Other current assets		170
Property and equipment, net		528
Goodwill		7,629
Intangible assets		14,800
Restricted cash		305
Other assets		12
Liabilities assumed:
Accounts payable		(908	)
Accrued and other current liabilities		(2,294	)
Other current liabilities		(30	)
Net assets acquired	$	29,572

Goodwill has been allocated to the miraDry reportable segment. The goodwill recognized is attributable primarily to the assembled workforce and additional market opportunities. Goodwill is not deductible for tax purposes.

A summary of the intangible assets acquired, estimated useful lives and amortization methods is as follows (in thousands):

			Estimated useful	Amortization
	Amount		life	method
Developed technology	$	3,000	15 years	Accelerated
Customer relationships		6,300	14 years	Accelerated
Distributor relationships		500	9 years	Accelerated
Trade name		5,000	15 years	Accelerated
	$	14,800

The Company retained an independent third-party appraiser to assist management in its valuation and the purchase price has been finalized.

Unaudited Pro Forma Information

The following unaudited pro forma financial information presents combined results of operations for each of the periods presented, as if miraDry had been acquired as of the beginning of fiscal year 2017. The pro forma information includes adjustments to amortization for intangible assets acquired, the purchase accounting effect on inventory acquired, interest expense for the additional indebtedness incurred to complete the acquisition, restructuring charges in connection with the acquisition and acquisition costs. The pro forma data are for informational purposes only and are not necessarily indicative of the condensed consolidated results of operations of the combined business had the merger actually occurred at the beginning of fiscal year 2017 or of the results of future operations of the combined business. Consequently, actual results will differ from the unaudited pro forma information presented below (in thousands, except per share amounts):

	Three Months Ended			Nine Months Ended
	September 30,			September 30,
	2017			2017
	Pro Forma			Pro Forma
Net sales	$	10,668		$	35,681
Net loss		(11,960	)		(56,053	)
Pro forma loss per share attributable to ordinary shares - basic and diluted	$	(0.62	)	$	(2.95	)

Fair Value of Financial Instruments

9 Months Ended

Sep. 30, 2018

Financial Instruments Owned At Fair Value [Abstract]

Fair Value of Financial Instruments

5.	Fair Value of Financial Instruments

The carrying amounts of cash and cash equivalents, accounts receivable, accounts payable, accrued liabilities, customer deposits and sales return liability are reasonable estimates of their fair value because of the short maturity of these items. The fair value of the common stock warrant liability and contingent consideration are discussed in Note 6. The fair value of the debt is based on the amount of future cash flows associated with the instrument discounted using the Company’s estimated market rate. As of September 30, 2018, the carrying value of the long-term debt was not materially different from the fair value.

Fair Value Measurements

9 Months Ended

Sep. 30, 2018

Fair Value Disclosures [Abstract]

Fair Value Measurements

6.	Fair Value Measurements

Certain assets and liabilities are carried at fair value under GAAP. Fair value is defined as the exchange price that would be received for an asset or paid to transfer a liability (an exit price) in the principal or most advantageous market for the asset or liability in an orderly transaction between market participants on the measurement date. Valuation techniques used to measure fair value must maximize the use of observable inputs and minimize the use of unobservable inputs. Financial assets and liabilities carried at fair value are to be classified and disclosed in one of the following three levels of the fair value hierarchy, of which the first two are considered observable and the last is considered unobservable:

•

Level 1 — Quoted prices in active markets for identical assets or liabilities.

•

Level 2 — Observable inputs (other than Level 1 quoted prices) such as quoted prices in active markets for similar assets or liabilities, quoted prices in markets that are not active for identical or similar assets or liabilities, or other inputs that are observable or can be corroborated by observable market data.

•

Level 3 — Unobservable inputs that are supported by little or no market activity and that are significant to determining the fair value of the assets or liabilities, including pricing models, discounted cash flow methodologies and similar techniques.

The Company’s common stock warrant liabilities are carried at fair value determined according to the fair value hierarchy described above. The Company has utilized an option pricing valuation model to determine the fair value of its outstanding common stock warrant liabilities. The inputs to the model include fair value of the common stock related to the warrant, exercise price of the warrant, expected term, expected volatility, risk-free interest rate and dividend yield. The warrants are valued using the fair value of common stock as of the measurement date. The Company historically has been a private company and lacks company-specific historical and implied volatility information of its stock. Therefore, it estimates its expected stock volatility based on the historical volatility of publicly traded peer companies for a term equal to the remaining contractual term of the warrants. The risk-free interest rate is determined by reference to the U.S. Treasury yield curve for time periods approximately equal to the remaining contractual term of the warrants. The Company has estimated a 0% dividend yield based on the expected dividend yield and the fact that the Company has never paid or declared dividends. As several significant inputs are not observable, the overall fair value measurement of the warrants is classified as Level 3.

The Company assessed the fair value of the contingent consideration for future royalty payments related to the acquisition of BIOCORNEUM, the contingent consideration for future milestone payments for the acquisition of the tissue expander portfolio and the contingent consideration for the future milestone payments related to the acquisition of miraDry using a Monte-Carlo simulation model. Significant assumptions used in the measurement include future net sales for a defined term and the risk-adjusted discount rate associated with the business. As the inputs are not observable, the overall fair value measurement of the contingent consideration is classified as Level 3.

The following tables present information about the Company’s liabilities that are measured at fair value on a recurring basis as of September 30, 2018 and December 31, 2017 and indicate the level of the fair value hierarchy utilized to determine such fair value (in thousands):

	Fair Value Measurements as of
	September 30, 2018 Using:
	Level 1		Level 2		Level 3		Total
Liabilities:
Liability for common stock warrants	$	—		—		527		527
Liability for contingent consideration		—		—		14,497		14,497
	$	—		—		15,024		15,024

	Fair Value Measurements as of
	December 31, 2017 Using:
	Level 1		Level 2		Level 3		Total
Liabilities:
Liability for common stock warrants	$	—		—		194		194
Liability for contingent consideration		—		—		12,319		12,319
	$	—		—		12,513		12,513

The liability for common stock warrants and the current portion of contingent consideration is included in “accrued and other current liabilities” and the long-term liabilities for the contingent consideration are included in “deferred and contingent consideration” in the condensed consolidated balance sheet. The following table provides a rollforward of the aggregate fair values of the Company’s common stock warrants and contingent consideration for which fair value is determined by Level 3 inputs (in thousands):

Warrant Liability
Balance, December 31, 2017	$	194
Change in fair value of warrant liability		333
Balance, September 30, 2018	$	527
Contingent Consideration Liability
Balance, December 31, 2017	$	12,319
Change in fair value of contingent consideration		2,178
Balance, September 30, 2018	$	14,497

The Company recognizes changes in the fair value of the warrants in “other income (expense), net” in the condensed consolidated statement of operations and changes in contingent consideration are recognized in “general and administrative” expense in the condensed consolidated statement of operations.

- Definition

The entire disclosure for the fair value of financial instruments (as defined), including financial assets and financial liabilities (collectively, as defined), and the measurements of those instruments as well as disclosures related to the fair value of non-financial assets and liabilities. Such disclosures about the financial instruments, assets, and liabilities would include: (1) the fair value of the required items together with their carrying amounts (as appropriate); (2) for items for which it is not practicable to estimate fair value, disclosure would include: (a) information pertinent to estimating fair value (including, carrying amount, effective interest rate, and maturity, and (b) the reasons why it is not practicable to estimate fair value; (3) significant concentrations of credit risk including: (a) information about the activity, region, or economic characteristics identifying a concentration, (b) the maximum amount of loss the entity is exposed to based on the gross fair value of the related item, (c) policy for requiring collateral or other security and information as to accessing such collateral or security, and (d) the nature and brief description of such collateral or security; (4) quantitative information about market risks and how such risks are managed; (5) for items measured on both a recurring and nonrecurring basis information regarding the inputs used to develop the fair value measurement; and (6) for items presented in the financial statement for which fair value measurement is elected: (a) information necessary to understand the reasons for the election, (b) discussion of the effect of fair value changes on earnings, (c) a description of [similar groups] items for which the election is made and the relation thereof to the balance sheet, the aggregate carrying value of items included in the balance sheet that are not eligible for the election; (7) all other required (as defined) and desired information.

+ References + Details

Product Warranties

9 Months Ended

Sep. 30, 2018

Product Warranties Disclosures [Abstract]

Product Warranties

7.	Product Warranties

The Company offers a product replacement and limited warranty program for the Company’s silicone gel breast implants, and a product warranty for the Company’s miraDry Systems and consumable bioTips, which the Company considers to be assurance-type warranties. For implants occurring prior to May 1, 2018, the Company provides replacement implants and revision surgery financial assistance, up to $3,600, for covered rupture events that occur within ten years of the implant surgery. The Company introduced its Platinum20 Limited Warranty Program in May 2018, covering OPUS breast implants implanted in the United States or Puerto Rico on or after May 1, 2018. The Company considers the program to have an assurance warranty component and a service warranty component. The service warranty component is discussed in Note 3. The assurance component is related to the lifetime no-charge contralateral replacement implants and revision surgery financial assistance, up to $5,000, for covered rupture events that occur within twenty years of the implant surgery. Under the miraDry warranty, the Company provides a standard product warranty for the miraDry system and bioTips.

The following table provides a rollforward of the accrued warranties (in thousands):

	Nine Months Ended September 30,
	2018			2017
Beginning balance as of January 1	$	1,642		$	1,378
Acquired warranty liability		—			137
Warranty costs incurred during the period		(395	)		(11	)
Changes in accrual related to warranties issued during the period		639			125
Changes in accrual related to pre-existing warranties		(637	)		8
Balance as of September 30	$	1,249		$	1,637

Net Loss Per Share

9 Months Ended

Sep. 30, 2018

Earnings Per Share [Abstract]

Net Loss Per Share

8.	Net Loss Per Share

Basic net loss per share attributable to common stockholders is computed by dividing net loss by the weighted average number of common shares outstanding during each period. Diluted net loss per common share is computed by dividing net loss available to common stockholders by the weighted average number of common shares and dilutive potential common share equivalents then outstanding, to the extent they are dilutive. Potential common shares consist of shares issuable upon the exercise of stock options and warrants (using the treasury stock method). Dilutive net loss per share is the same as basic net loss per share for all periods presented because the effects of potentially dilutive items were anti-dilutive.

	Three Months Ended September 30,						Nine Months Ended September 30,
	2018			2017			2018			2017
Net loss (in thousands)	$	(20,545	)	$	(14,381	)	$	(57,996	)	$	(46,192	)
Weighted average common shares outstanding, basic and diluted		28,462,975			19,328,244			24,312,300			19,079,788
Net loss per share attributable to common stockholders	$	(0.72	)	$	(0.74	)	$	(2.39	)	$	(2.42	)

The Company excluded the following potentially dilutive securities, outstanding as of September 30, 2018 and 2017, from the computation of diluted net loss per share attributable to common stockholders for the three and nine months ended September 30, 2018 and 2017 because they had an anti-dilutive impact due to the net loss attributable to common stockholders incurred for the periods.

	September 30,
	2018		2017
Stock options to purchase common stock		1,926,835		1,872,999
Warrants for the purchase of common stock		47,710		47,710
		1,974,545		1,920,709

Balance Sheet Components

9 Months Ended

Sep. 30, 2018

Balance Sheet Related Disclosures [Abstract]

Balance Sheet Components

9.	Balance Sheet Components

a.

Allowance for Doubtful Accounts

The Company has established an allowance for doubtful accounts of $1.4 million and $0.9 million as of September 30, 2018 and December 31, 2017, respectively, recorded net against accounts receivable in the balance sheet.

b.

Inventories

Inventories, net consist of the following (in thousands):

	September 30,		December 31,
	2018		2017
Raw materials	$	1,946	$	1,642
Work in progress		1,806		3,956
Finished goods		17,805		15,298
Finished goods - right of return		1,352		—
	$	22,909	$	20,896

c.

Prepaid Expenses and Other Current Assets

Prepaid expenses and other current assets consist of the following (in thousands):

	September 30,		December 31,
	2018		2017
Prepaid expenses	$	2,370	$	1,040
Other current assets		1,112		472
Total	$	3,482	$	1,512

d.

Property and Equipment

Property and equipment, net consist of the following (in thousands):

	September 30,			December 31,
	2018			2017
Leasehold improvements	$	402		$	402
Manufacturing equipment and toolings		1,809			4,260
Computer equipment		478			387
Software		1,023			797
Office equipment		156			142
Furniture and fixtures		820			816
		4,688			6,804
Less accumulated depreciation		(2,248	)		(2,041	)
	$	2,440		$	4,763

Depreciation expense for both the three months ended September 30, 2018 and 2017 was $0.2 million. Depreciation expense for the nine months ended September 30, 2018 and 2017 was $0.9 million and $0.6 million, respectively.

Under the terms of the manufacturing agreement with Vesta, upon the commencement of Contract Year One (as defined in the agreement) which occurred following FDA-approval of all submissions related to the site-change PMA supplement for the Vesta manufacturing facility Vesta is obligated to purchase the manufacturing equipment and tooling that Sientra had originally purchased for the manufacture of Sientra’s breast implant inventory at Vesta’s manufacturing facility. Vesta repurchased the equipment with a net book value of $2.7 million in the third quarter of 2018 through a reduction in the Company’s accounts payable balance owed to Vesta.

e.

Goodwill and Other Intangible Assets, net

Goodwill represents the excess of the purchase price over the fair value of net assets of purchased businesses. Goodwill is not amortized, but instead subject to impairment tests on at least an annual basis and whenever circumstances suggest that goodwill may be impaired. The Company’s annual test for impairment is performed as of October 1 of each fiscal year. The Company makes a qualitative assessment of whether it is more likely than not that a reporting unit’s fair value is less than its carrying amount. If the Company concludes that it is not more likely than not that the fair value of a reporting unit is less than its carrying amount, it is not required to perform the impairment assessment for that reporting unit.

The applicable accounting guidance requires the Company to compare the fair value of a reporting unit with its carrying amount, including goodwill. If the fair value of a reporting unit exceeds its carrying amount, goodwill of the reporting unit is not considered impaired. The impairment loss is measured by the excess of the carrying amount of the reporting unit goodwill over the fair value of that goodwill.

The changes in the carrying amount of goodwill during the nine months ended September 30, 2018 were as follows (in thousands):

	Breast Products			miraDry		Total
Balances as of December 31, 2017
Goodwill	$	19,156		$	7,629	$	26,785
Accumulated impairment losses		(14,278	)		—		(14,278	)
Goodwill, net	$	4,878		$	7,629	$	12,507

Balances as of September 30, 2018
Goodwill	$	19,156		$	7,629	$	26,785
Accumulated impairment losses		(14,278	)		—		(14,278	)
Goodwill, net	$	4,878		$	7,629	$	12,507

The components of the Company’s other intangible assets consist of the following (in thousands):

	Average
	Amortization		September 30, 2018
	Period		Gross Carrying		Accumulated			Intangible
	(in years)		Amount		Amortization			Assets, net
Intangibles with definite lives
Customer relationships		11	$	11,240	$	(3,078	)	$	8,162
Trade names - finite life		14		5,800		(460	)		5,340
Developed technology		15		3,000		(277	)		2,723
Distributor relationships		9		500		(108	)		392
Non-compete agreement		2		80		(78	)		2
Regulatory approvals		1		670		(670	)		—
Acquired FDA non-gel product approval		11		1,713		(1,713	)		—
Total definite-lived intangible assets			$	23,003	$	(6,384	)	$	16,619

Intangibles with indefinite lives
Trade names - indefinite life	—			450		—			450
Total indefinite-lived intangible assets			$	450	$	—		$	450

	Average
	Amortization		December 31, 2017
	Period		Gross Carrying		Accumulated			Intangible
	(in years)		Amount		Amortization			Assets, net
Intangibles with definite lives
Customer relationships		11	$	11,240	$	(1,859	)	$	9,381
Trade names - finite life		14		5,800		(216	)		5,584
Developed technology		15		3,000		(95	)		2,905
Distributor relationships		9		500		(40	)		460
Non-compete agreement		2		80		(57	)		23
Regulatory approvals		1		670		(670	)		—
Acquired FDA non-gel product approval		11		1,713		(1,713	)		—
Total definite-lived intangible assets			$	23,003	$	(4,650	)	$	18,353

Intangibles with indefinite lives
Trade names - indefinite life	—			450		—			450
Total indefinite-lived intangible assets			$	450	$	—		$	450

Amortization expense for the three months ended September 30, 2018 and 2017 was $0.6 million and $1.0 million, respectively. Amortization expense for the nine months ended September 30, 2018 and 2017 was $1.7 million and $1.8 million, respectively. The following table summarizes the estimated amortization expense relating to the Company's definite-lived intangible assets as of September 30, 2018 (in thousands):

	Amortization
Period	Expense
Remainder of 2018	$	574
2019		2,321
2020		2,209
2021		1,996
2022		1,762
Thereafter		7,757
	$	16,619

f.

Accrued and Other Current Liabilities

Accrued and other current liabilities consist of the following (in thousands):

	September 30,		December 31,
	2018		2017
Payroll and related expenses	$	6,818	$	3,579
Accrued commissions		2,978		3,297
Accrued equipment		200		1,091
Deferred and contingent consideration, current portion		8,440		977
Audit, consulting and legal fees		768		920
Accrued sales and marketing expenses		1,255		794
Other		4,759		2,816
	$	25,218	$	13,474

Long-Term Debt and Revolving Loan

9 Months Ended

Sep. 30, 2018

Debt Disclosure [Abstract]

Long-Term Debt and Revolving Loan

10.	Long-Term Debt and Revolving Loan

On July 25, 2017, the Company entered into a Credit and Security Agreement, or the Term Loan Credit Agreement, and a Credit and Security Agreement, or the Revolving Credit Agreement with MidCap, and, together with the Term Loan Credit Agreement, the Credit Agreements, which replaced the Company’s then-existing Silicon Valley Bank Loan Agreement, or the SVB Loan Agreement.

Under the terms of the Term Loan Credit Agreement, as of July 25, 2017, MidCap funded $25.0 million to the Company, or the Closing Date Term Loan. MidCap also made available to the Company until March 31, 2018, a $10.0 million term loan, or the March 2018 Term Loan, subject to the satisfaction of certain conditions, including FDA certifications of the manufacturing facility operated by Vesta, and an additional $5.0 million term loan, subject to the satisfaction of certain conditions, including evidence that the Company’s Net Revenue for the past 12 months was greater than or equal to $75.0 million, as defined in the Term Loan Credit Agreement, collectively the Term Loans. On April 18, 2018, the Company amended the Term Loan Credit Agreement pursuant to which the parties agreed to adjust the date by which the Company must obtain FDA approval of its PMA supplement in order to access the March 2018 Term Loan until April 30, 2018. In April 2018, upon FDA approval of the Company’s PMA supplement, MidCap funded the $10.0 million March Term Loan. Under the Revolving Credit Agreement, MidCap made available to the Company a revolving line of credit, or the Revolving Loan. The amount of loans available to be drawn is based on a borrowing base equal to 85% of the net collectible value of eligible accounts receivable plus 40% of eligible finished goods inventory, or the Borrowing Base, provided that availability from eligible finished goods inventory does not exceed 20% of the Borrowing Base. The Company used a portion of the $25.0 million of proceeds from the Closing Date Term Loan to repay in full the Company’s then-existing indebtedness under its SVB Loan Agreement and to pay fees and expenses in connection with the foregoing and the Company intends to use the remainder of the proceeds for general corporate purposes.

Any indebtedness under the Term Loan Credit Agreement bears interest at a floating per annum rate equal to the LIBOR as reported by MidCap with a floor of 1.00%, which as of September 30, 2018 was 2.10%, plus 7.50%. The Term Loans have a scheduled maturity date of December 1, 2021, or the Maturity Date. The Company must make monthly payments of accrued interest under the Term Loans from the funding date of the Term Loans, until December 31, 2018, followed by monthly installments of principal and interest through the Maturity Date. Under the terms of the Term Loan Credit Agreement, the Company has the option to extend the interest only period an additional six months to June 30, 2019 as long as the Company remains in compliance with the Term Loan Agreement. As of September 30, 2018, the Company intends to extend the interest only period through June 30, 2019. The Company may prepay all of the Term Loans prior to its maturity date provided the Company pays MidCap a prepayment fee. The Company paid an origination fee of 0.50% of the Term Loans total amount of $40.0 million on the closing date. As of September 30, 2018, there was $35.0 million outstanding related to the Term Loans. As of September 30, 2018, the unamortized debt issuance costs on the Term Loans was approximately $0.1 million current portion and approximately $0.1 million long-term portion and are included as a reduction to debt on the condensed consolidated balance sheet.

Any indebtedness under the Revolving Credit Agreement bears interest at a floating per annum rate equal to the LIBOR as reported by MidCap with a floor of 1.00%, plus 4.50%. The Company may make and repay borrowings from time to time under the Revolving Credit Agreement until the maturity of the facility on December 1, 2021. The Company is required to pay an annual collateral management fee of 0.50% on the outstanding balance, and an annual unused line fee of 0.50% of the average unused portion. The Company paid an origination fee of 0.50% of the Revolving Loan amount of $10.0 million on the closing date. The Company classifies the amounts borrowed under the Revolving Loan as short term because it is the Company's intention to use the line of credit to borrow and pay back funds over short periods of time. As of September 30, 2018, there were no borrowings outstanding under the Revolving Loan. As of September 30, 2018, the unamortized debt issuance costs related to the Revolving Loan was approximately $0.1 million and was included in other long-term assets on the condensed consolidated balance sheet.

The amortization of debt issuance costs for the three months ended September 30, 2018 and 2017 was $47,000 and $28,500, respectively. The amortization of debt issuance costs for both the nine months ended September 30, 2018 and 2017 was $0.1 million, and was included in interest expense in the condensed consolidated statements of operations.

The Credit Agreements include customary affirmative and restrictive covenants and representations and warranties, including a financial covenant for minimum revenues, a financial covenant for minimum cash requirements, a covenant against the occurrence of a “change in control,” financial reporting obligations, and certain limitations on indebtedness, liens, investments, distributions, collateral, mergers or acquisitions, taxes, and deposit accounts. Upon the occurrence of an event of default, a default interest rate of an additional 5.0% may be applied to any outstanding principal balances, and MidCap may declare all outstanding obligations immediately due and payable and take such other actions as set forth in the Credit Agreements. The Company’s obligations under the Credit Agreements are secured by a security interest in substantially all of The Company’s assets.

Future Principal Payments of Debt

The future schedule of principal payments for the outstanding Term Loans as of September 30, 2018 was as follows (in thousands):

Fiscal Year
2019	$	7,000
2020		14,000
2021		14,000
2022		—
2023		—
Thereafter		—
Total	$	35,000

Stockholders' Equity

9 Months Ended

Sep. 30, 2018

Disclosure Of Compensation Related Costs Sharebased Payments [Abstract]

Stockholders' Equity

11.Stockholders’ Equity

a.

Authorized Stock

The Company’s Amended and Restated Certificate of Incorporation authorizes the Company to issue 210,000,000 shares of common and preferred stock, consisting of 200,000,000 shares of common stock with $0.01 par value and 10,000,000 shares of preferred stock with $0.01 par value. As of September 30, 2018 and December 31, 2017, the Company had no preferred stock issued or outstanding.

b.

Common Stock Warrants

On January 17, 2013, the Company entered into a Loan and Security Agreement, or the Original Term Loan Agreement, with Oxford Finance, LLC, or Oxford. On June 30, 2014, the Company entered into an Amended and Restated Loan and Security Agreement, or the Amended Term Loan Agreement, with Oxford. In connection with the Original Term Loan Agreement and the Amended Term Loan Agreement, the Company issued to Oxford (i) seven-year warrants in January 2013 to purchase shares of the Company’s common stock with a value equal to 3.0% of the tranche A, B and C term loans amounts and (ii) seven-year warrants in June 2014 to purchase shares of the Company’s common stock with a value equal to 2.5% of the tranche D term loan amount. The warrants have an exercise price per share of $14.671. As of September 30, 2018, there were warrants to purchase an aggregate of 47,710 shares of common stock outstanding.

c.

Stock Option Plans

In April 2007, the Company adopted the 2007 Equity Incentive Plan, or the 2007 Plan. The 2007 Plan provides for the granting of stock options to employees, directors and consultants of the Company. Options granted under the 2007 Plan may either be incentive stock options or nonstatutory stock options. Incentive stock options, or ISOs, may be granted only to Company employees. Nonstatutory stock options, or NSOs, may be granted to all eligible recipients. A total of 1,690,448 shares of the Company’s common stock were initially reserved for issuance under the 2007 Plan.

The Company’s board of directors adopted the 2014 Equity Incentive Plan, or 2014 Plan, in July 2014, and the stockholders approved the 2014 Plan in October 2014. The 2014 Plan became effective upon completion of the IPO on November 3, 2014, at which time the Company ceased granting awards under the 2007 Plan. Under the 2014 Plan, the Company may issue ISOs, NSOs, stock appreciation rights, restricted stock awards, restricted stock unit awards and other forms of stock awards, or collectively, stock awards, all of which may be granted to employees, including officers, non-employee directors and consultants of the Company and their affiliates. ISOs may be granted only to employees. A total of 1,027,500 shares of common stock were initially reserved for issuance under the 2014 Plan, subject to certain annual increases. As of September 30, 2018, a total of 132,719 shares of the Company’s common stock were available for issuance under the 2014 Plan.

Pursuant to a board-approved Inducement Plan, the Company may issue NSOs and restricted stock unit awards, or collectively, stock awards, all of which may only be granted to new employees of the Company and their affiliates in accordance with NASDAQ Stock Market Rule 5635(c)(4) as an inducement material to such individuals entering into employment with the Company. As of September 30, 2018, inducement grants for 876,441 shares of common stock have been awarded, and 91,306 shares of common stock were available for future issuance under the Inducement Plan.

Options under the 2007 Plan and the 2014 Plan may be granted for periods of up to ten years as determined by the Company’s board of directors, provided, however, that (i) the exercise price of an ISO shall not be less than 100% of the estimated fair value of the shares on the date of grant, and (ii) the exercise price of an ISO granted to a more than 10% shareholder shall not be less than 110% of the estimated fair value of the shares on the date of grant. An NSO has no such exercise price limitations. NSOs under the Inducement Plan may be granted for periods of up to ten years as determined by the board of directors, provided, the exercise price will not be less than 100% of the estimated fair value of the shares on the date of grant. Options generally vest with 25% of the grant vesting on the first anniversary and the balance vesting monthly on a straight-lined basis over the requisite service period of three additional years for the award. Additionally, options have been granted to certain key executives that vest upon achievement of performance conditions based on performance targets as defined by the board of directors, which have included net sales targets and defined corporate objectives over the performance period with possible payout ranging from 0% to 100% of the target award. Compensation expense is recognized on a straight-lined basis over the vesting term of one year based upon the probable performance target that will be met. The vesting provisions of individual options may vary but provide for vesting of at least 25% per year.

The following summarizes all option activity under the 2007 Plan, 2014 Plan and Inducement Plan:

				Weighted		Weighted average
				average		remaining
	Option			exercise		contractual
	Shares			price		term (year)
Balances at December 31, 2017		2,179,787		$	7.60		7.27
Exercised		(147,463	)		7.79
Forfeited		(77,341	)		11.44
Balances at September 30, 2018		1,954,983		$	7.43		6.56

For stock-based awards the Company recognizes compensation expense based on the grant date fair value using the Black-Scholes option valuation model. Stock-based compensation expense related to stock options was $0.5 million for both the three months ended September 30, 2018 and 2017. Stock-based compensation expense related to stock options was $1.3 million and $1.6 million for the nine months ended September 30, 2018 and 2017, respectively. As of September 30, 2018, there was $1.2 million of unrecognized compensation costs related to stock options. The expense is recorded within the operating expense components in the condensed consolidated statement of operations based on the recipients receiving the awards. These costs are expected to be recognized over a weighted average period of 1.45 years.

d.

Restricted Stock Units

The Company has issued restricted stock unit awards, or RSUs, under the 2014 Plan and the Inducement Plan. The RSUs issued to employees generally vest on a straight-line basis, either quarterly over a 4-year requisite service period or annually over a 3-year requisite service period. RSUs issued to non-employees generally vest either monthly or annually over the service term.

Activity related to RSUs is set forth below:

				Weighted average
	Number			grant date
	of shares			fair value
Balances at December 31, 2017		928,552		$	9.12
Granted		1,738,940			13.98
Vested		(464,507	)		10.18
Forfeited		(154,112	)		11.23
Balances at September 30, 2018		2,048,873		$	12.84

Stock-based compensation expense for RSUs for the three months ended September 30, 2018 and 2017 was $3.8 million and $1.0 million, respectively. Stock-based compensation expense for RSUs for the nine months ended September 30, 2018 and 2017 was $8.4 million and $2.8 million respectively. As of September 30, 2018, there was $23.8 million of total unrecognized compensation costs related to non-vested RSU awards. The cost is expected to be recognized over a weighted average period of 2.33 years.

e.

Employee Stock Purchase Plan

The Company’s board of directors adopted the 2014 Employee Stock Purchase Plan, or ESPP, in July 2014, and the stockholders approved the ESPP in October 2014. The ESPP allows eligible employees to purchase shares of the Company’s common stock at a discount through payroll deductions of up to 15% of their eligible compensation, subject to any plan limitations. The ESPP provides for offering periods not to exceed 27 months, and each offering period will include purchase periods, which will be the approximately six-month period commencing with one exercise date and ending with the next exercise date. Employees are able to purchase shares at 85% of the lower of the fair market value of the Company’s common stock on the first trading day of the offering period or on the purchase date. A total of 255,500 shares of common stock were initially reserved for issuance under the ESPP, subject to certain annual increases.

During the nine months ended September 30, 2018, employees purchased 145,616 shares of common stock at a weighted average price of $6.82 per share. As of September 30, 2018, the number of shares of common stock available for future issuance was 543,955.

The Company estimated the fair value of employee stock purchase rights using the Black-Scholes model. Stock-based compensation expense related to the ESPP was $0.2 million and $0.1 million for the three months ended September 30, 2018 and 2017, respectively. Stock-based compensation expense related to the ESPP was $0.4 million and $0.3 million for the nine months ended September 30, 2018 and 2017, respectively.

Income Taxes

9 Months Ended

Sep. 30, 2018

Income Tax Disclosure [Abstract]

Income Taxes

12.	Income Taxes

The Company operates in several tax jurisdictions and is subject to taxes in each jurisdiction in which it conducts business. To date, the Company has incurred cumulative net losses and maintains a full valuation allowance on its net deferred tax assets due to the uncertainty surrounding realization of such assets. Tax expense was $0 and $16,000 for the three months ended September 30, 2018 and 2017, respectively. Tax expense was $0 and $0.1 million for the nine months ended September 30, 2018 and 2017, respectively.

Segment Information

9 Months Ended

Sep. 30, 2018

Segment Reporting [Abstract]

Segment Information

13.	Segment Information

Reportable Segments

The Company has two reportable segments: Breast Products and miraDry. The Breast Products segment focuses on sales of silicone gel breast implants, tissue expanders and scar management products under the brands Sientra, AlloX2, Dermaspan, Softspan and BIOCORNEUM. The miraDry segment focuses on sales of the miraDry System, consisting of a console and a handheld device which uses consumable single-use bioTips. These segments align with the Company’s principal target markets. On July 25, 2017, the Company acquired miraDry. See Note 4 – Acquisitions for additional details. miraDry has been included in the condensed consolidated results of operations as of the Acquisition Date and financial performance of the acquired business is reported in the miraDry segment. The segments represent components for which separate financial information is available that is utilized on a regular basis by the Chief Executive Officer, who has been identified as the Chief Operating Decision Maker, or CODM, as defined by authoritative guidance on segment reporting, in determining how to allocate resources and evaluate performance. The segments are determined based on several factors, including client base, homogeneity of products, technology, delivery channels and similar economic characteristics.

The Company’s CODM assesses the performance of each segment and allocates resources to those segments based on net sales and operating income (loss). Operating income (loss) by segment includes items that are directly attributable to each segment, including sales and marketing functions, as well as finance, information technology, human resources, legal and related corporate infrastructure costs, along with certain benefit-related expenses. There are no unallocated expenses for the two segments.

The following tables present the net sales, net operating loss and net assets by reportable segment for the periods presented (in thousands):

	Three Months Ended				Nine Months Ended
	September 30,				September 30,
	2018		2017		2018		2017
Net sales
Breast Products	$	8,613	$	7,655	$	26,566	$	23,313
miraDry		8,262		2,164		22,538		2,164
Total net sales	$	16,875	$	9,819	$	49,104	$	25,477

	Three Months Ended				Nine Months Ended
	September 30,				September 30,
	2018		2017		2018		2017
Loss from operations
Breast Products	$	13,873	$	11,253	$	39,111	$	42,878
miraDry		5,689		2,602		16,278		2,602
Total loss from operations	$	19,562	$	13,855	$	55,389	$	45,480

	September 30,		December 31,
	2018		2017
Assets
Breast Products	$	144,333	$	59,365
miraDry		36,747		32,848
Total assets	$	181,080	$	92,213

Commitments and Contingencies

9 Months Ended

Sep. 30, 2018

Commitments And Contingencies Disclosure [Abstract]

Commitments and Contingencies

14.	Commitments and Contingencies

a.

Operating Leases

The Company’s leases for its general office facilities are in Santa Barbara, California and Santa Clara, California, with leases expiring February 2020 and May 2024, respectively. The Company also leases additional industrial space for warehouse, research and development and additional general office use. Rent expense was $0.3 million and $0.2 million for the three months ended September 30, 2018 and 2017, respectively. Rent expense was $0.9 million and $0.5 million for the nine months ended September 30, 2018 and 2017, respectively. The Company recognizes rent expense on a straight-line basis over the lease term.

b.

Contingencies

The Company is subject to claims and assessment from time to time in the ordinary course of business. The Company accrues a liability for such matters when it is probable that future expenditures will be made and such expenditures can be reasonably estimated.

Class Action Shareholder Litigation

On September 25, 2015, a lawsuit styled as a class action of the Company’s stockholders was filed in the United States District Court for the Central District of California naming the Company and certain of its officers as defendants for allegedly false and misleading statements concerning the Company’s business, operations, and prospects. On October 28, November 5, and November 19, 2015, three lawsuits styled as class actions of the Company’s stockholders were filed in the Superior Court of California for the County of San Mateo naming the Company, certain of its officers and directors, and the underwriters associated with the Company’s follow-on public offering that closed on September 23, 2015 as defendants for allegedly false and misleading statements in the Company’s offering documents associated with the follow-on offering concerning its business, operations, and prospects. On September 13, 2016, the parties to the actions pending in the San Mateo Superior Court and the United States District Court for the Central District of California signed a memorandum of understanding that sets forth the material deal points of a settlement that covers both actions and includes class-wide relief. Following a final fairness hearing in the federal court, on May 23, 2017, the federal court extended an order granting final approval of the settlement and dismissing the federal court action with prejudice. Following a final fairness hearing in the state court, on May 31, 2017, the state court entered an order granting final approval of the settlement and dismissing the state court action with prejudice.

As a result of these developments, the Company determined a probable loss had been incurred and recognized a net charge to earnings of approximately $1.6 million for the nine months ended September 30, 2016 within general and administrative expense which was comprised of the loss contingency of approximately $10.9 million, net of expected insurance proceeds of approximately $9.4 million. In the first quarter of 2017, the Company received $9.3 million in insurance proceeds and paid the $10.9 million loss contingency. The remaining insurance proceeds receivable is classified as “prepaid expenses and other current assets” on the accompanying condensed consolidated balance sheets.

miraDry Class Action Litigation

On August 3, 2017, a lawsuit styled as a verified class action on the part of the former stockholders of miraDry was filed in the Court of Chancery for the State of Delaware against the former board of directors of miraDry, or the Defendants, alleging breach of their fiduciary duties in connection with the Company’s acquisition of miraDry. On August 30, 2017, the Defendants moved to dismiss the verified class action complaint for failure to state a claim upon which relief can be granted. On November 11, 2017 the parties notified the Court that they had reached an agreement to settle the matter pending completion of confirmatory discovery regarding the fairness of the settlement and obtaining approval from the court. Under the terms of the proposed settlement, in exchange for a full and final settlement and release of all claims, the Defendants (and/or their indemnitors and/or insurers) agreed to pay a settlement consideration of $0.4 million. The miraDry Merger Agreement contained a holdback amount expected to be used for the settlement and associated costs of the miraDry Class Action litigation. The holdback amount has been used to offset $0.6 million of legal fees and $0.4 million is included in “legal settlement payable” on the condensed consolidated balance sheet as of September 30, 2018.

Silimed Litigation

On July 27, 2017, the Company entered into a settlement agreement, or the Settlement Agreement, with Silimed to settle outstanding litigations with Silimed. Pursuant to the Settlement Agreement, in exchange for a mutual release of claims and covenants not to sue or pursue certain litigation, Sientra paid Silimed a lump sum of $9.0 million on September 7, 2017 and paid an additional $1.0 million on June 29, 2018. In addition, should the Company enter into international markets using certain breast implant specifications, the Company has agreed to make royalty payments of $12.5 on each of its net sales of such products, up to a maximum royalty of $5.0 million.

It is possible that additional suits will be filed, or allegations made by stockholders, with respect to these same or other matters and also naming the Company and/or its officers and directors as defendants. The Company believes it has meritorious defenses and intends to defend these lawsuits vigorously.

Subsequent Events	9 Months Ended
Subsequent Events	Sep. 30, 2018
Subsequent Events [Abstract]
Subsequent Events	15.Subsequent Events Amendment of Lease On October 19, 2018, miraDry, entered into a First Amendment to the Lease, or the Lease Amendment, effective October 9, 2018 with IPX Walsh Bowers Investors, L.P., or the Landlord. The Lease Amendment amends the Lease dated December 16, 2013, as amended, or collectively, the Lease, for the office space located at 2845 Bowers Avenue, 2855 Bowers Avenue, and 2790 Walsh Avenue, Santa Clara, California containing approximately 29,256 rentable square feet, or the Premises. The Lease Amendment extends the term for the Lease for a period of sixty-two (62) months until its new expiration on July 31, 2024. Pursuant to the Lease Amendment, miraDry agreed to provide an amendment to its existing letter of credit in the amount of $0.3 million to extend the expiration date of such letter until September 30, 2024.

Summary of Significant Accounting Policies (Policies)

9 Months Ended

Sep. 30, 2018

Accounting Policies [Abstract]

Basis of Presentation

a.

Basis of Presentation

The accompanying unaudited condensed consolidated financial statements in this Quarterly Report on Form 10-Q have been prepared in accordance with accounting principles generally accepted in the United States of America, or GAAP, and the rules and regulations of the U.S. Securities and Exchange Commission, or SEC. Accordingly, they do not include certain footnotes and financial presentations normally required under accounting principles generally accepted in the United States of America for complete financial reporting. The interim financial information is unaudited, but reflects all normal adjustments and accruals which are, in the opinion of management, considered necessary to provide a fair presentation for the interim periods presented. The accompanying condensed consolidated financial statements should be read in conjunction with the Company’s audited consolidated financial statements and notes thereto included in the Company’s Annual Report on Form 10-K for the year ended December 31, 2017 filed with the SEC on March 13, 2018 and Form 10-K/A filed on April 30, 2018, or the Annual Report. The results for the three and nine months ended September 30, 2018 are not necessarily indicative of results to be expected for the year ending December 31, 2018, any other interim periods, or any future year or period.

Liquidity

b.

Liquidity

Since the Company’s inception, it has incurred significant net operating losses and the Company anticipates that losses will continue in the near term. The Company expects its operating expenses will continue to grow as they expand operations. The Company will need to generate significant net sales to achieve profitability. To date, the Company has funded operations primarily with proceeds from the sales of preferred stock, borrowings under term loans, sales of products since 2012, and the proceeds from the sale of common stock in public offerings.

The accompanying condensed consolidated financial statements have been prepared on a going concern basis, which implies the Company will continue to realize its assets and discharge its liabilities in the normal course of business. As of September 30, 2018, the Company had cash and cash equivalents of $103.0 million. Since inception, the Company has incurred recurring losses from operations and cash outflows from operating activities. The continuation of the Company as a going concern is dependent upon many factors including liquidity and the ability to raise capital. The Company received FDA approval of their PMA supplement on April 17, 2018 and was then able to access a $10.0 million term loan pursuant to an amendment to the credit agreement with MidCap Financial Trust, or MidCap. In addition, in February 2018, the Company entered into an At-The-Market Equity Offering Sales Agreement with Stifel, Nicolaus & Company, Incorporated, or Stifel, as sales agent pursuant to which the Company may sell, from time to time, through Stifel, shares of our common stock having an aggregate gross offering price of up to $50.0 million. As of September 30, 2018, the Company has not sold any common stock pursuant to the sales agreement. Further, on May 7, 2018, the Company completed a public offering of its common stock, raising approximately $107.6 million in net proceeds after deducting underwriting discounts and commissions and other offering expenses.

The Company believes that its cash and cash equivalents will be sufficient to fund its operations for at least the next 12 months. To fund ongoing operating and capital needs, the Company may need to raise additional capital in the future through the sale of equity securities and incremental debt financing.

Use of Estimates

c.

Use of Estimates

The preparation of the condensed consolidated financial statements, in conformity with GAAP, requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities and disclosure of contingent assets and liabilities at the date of the condensed consolidated financial statements and the reported amounts of revenues and expenses during the reporting periods. Actual results could differ from those estimates.

Significant Accounting Policies

d.

Significant Accounting Policies

Revenue Recognition

The Company recognizes revenue when the Company transfers control of promised goods or services to customers in an amount that reflects the consideration to which the Company expects to be entitled to in exchange for those goods or services. See Note 3 - Revenue for further discussion.

There have been no other changes to the accounting policies during the three and nine months ended September 30, 2018, as compared to the significant accounting policies described in the “Notes to Financial Statements” in the Annual Report.

Recent Accounting Pronouncements

e.

Recent Accounting Pronouncements

Recently Adopted Accounting Standards

In June 2018, the FASB issued ASU 2018-07, Compensation - Stock Compensation (Topic 718), to simplify the accounting for non-employee share-based payment transactions by expanding the scope of ASC Topic 718 to include share-based payment transactions for acquiring goods and services from non-employees. Under the new standard, most of the guidance on stock compensation payments to non-employees would be aligned with the requirements for share-based payments granted to employees. ASU 2018-07 supersedes Subtopic 505-50, Equity—Equity-Based Payments to Non-Employees, and is effective for all public entities for fiscal years beginning after December 15, 2018, and interim periods within those fiscal years. Early adoption is permitted, but no earlier than a company’s adoption date of Topic 606, Revenue from Contracts with Customers. The Company early adopted ASU 2018-07 in the third quarter of 2018 and there was no material impact on its consolidated financial statements from the adoption.

In May 2014, the FASB issued ASU 2014-09, Revenue from Contracts with Customers (Topic 606). Topic 606 supersedes the revenue recognition requirements in Topic 605 Revenue Recognition (Topic 605) and requires entities to recognize revenue when control of the promised goods or services is transferred to customers at an amount that reflects the consideration to which the entity expects to be entitled to in exchange for those goods or services. The Company adopted Topic 606 in the first quarter of 2018 to all contracts using the modified retrospective method. The adoption of Topic 606 did not have a material impact on the Company’s historical net losses and, therefore, no adjustment was made to the opening balance of retained earnings. The comparative information has not been restated and continues to be reported under the accounting standards in effect for those periods.

In accordance with Topic 606 disclosure requirements, the impact of adoption on the Company’s condensed consolidated balance sheet was as follows (in thousands):



	As Reported		Total		Adjusted
	December 31, 2017		Adjustment		January 1, 2018
Balance Sheet
Assets
Accounts receivable, net of allowances	$	6,569		3,906		10,475
Liabilities
Sales return liability	$	—		3,906		3,906



	As Reported		Total			Amounts Under
	September 30, 2018		Adjustment			Previous Standards
Balance Sheet
Assets
Accounts receivable, net of allowances	$	18,956		(5,335	)		13,621
Liabilities
Sales return liability	$	5,335		(5,335	)		—

Additionally, in accordance with Topic 606, the balance of breast product inventory estimated to be returned as of September 30, 2018 is included in the components of the Company’s inventory as “finished goods – right of return” in Note 9b - Inventories. Prior to the adoption of Topic 606, the inventory impact of estimated returns for breast products was included in the “finished goods” inventory balance and was not separately disclosed.

The adoption of Topic 606 did not have a material impact on the Company’s condensed consolidated statement of operations.

In August 2016, the FASB issued ASU 2016-15, Statement of Cash Flows – Classifications of Certain Cash Receipts and Cash Payments (Topic 230). The standard update addresses eight specific cash flow issues not currently addressed by GAAP, with the objective of reducing the existing diversity in practice of how these cash receipts and payments are presented and classified in the statement of cash flows. The ASU requires a retrospective approach to adoption. The Company adopted the ASU in the first quarter of 2018. The adoption of this ASU did not have a material impact on the Company’s condensed consolidated financial statements.

In January 2017, the FASB issued ASU 2017-01, Business Combinations (Topic 805) - Clarifying the Definition of a Business. The standard adds guidance to assist entities with evaluating whether transactions should be accounted for as acquisitions (or disposals) of assets or businesses by providing a more specific definition of a business. The Company adopted the ASU in the first quarter of 2018 on a prospective basis. The adoption of this ASU did not have a material impact on the Company’s condensed consolidated financial statements.

In May 2017, the FASB issued ASU 2017-09, Compensation—Stock Compensation (Topic 718): Scope of Modification Accounting. The standard provides clarification on when modification accounting should be used for changes to the terms or conditions of a share-based payment award to which an entity would be required to apply modification accounting under Accounting Standard Codification, or ASC, 718. The Company adopted the ASU in the first quarter of 2018 on a prospective basis. The adoption of this ASU did not have a material impact on the Company’s condensed consolidated financial statements.

Recently Issued Accounting Standards

In February 2016, the FASB issued ASU 2016-02, Leases (Topic 842) which supersedes FASB Accounting Standard Codification Leases (Topic 840). The standard is intended to increase the transparency and comparability among organizations by recognizing lease assets and lease liabilities on the balance sheet and disclosing key information about leasing arrangements. This accounting standard update will be effective for the Company beginning in fiscal year 2019. In July 2018, the FASB issued ASU 2018-11, Leases (Topic 842): Targeted Improvements, which, among other things, allows companies to elect an optional transition method to apply the new lease standard through a cumulative-effect adjustment in the period of adoption. The Company is currently evaluating the impact that adoption of these standards will have on the financial statements and related disclosures.

In February 2018, the FASB issued ASU 2018-02, Income Taxes (Topic 740), which allows for an entity to elect to reclassify the income tax effects on items within accumulated other comprehensive income resulting from U.S. Tax Cuts and Jobs Act to retained earnings. The guidance is effective for fiscal years beginning after December 15, 2018 with early adoption permitted, including interim periods within those years. The Company does not expect to elect to reclassify the income tax effects under ASU 2018-05, as it does not have a material impact on the condensed consolidated financial statements.

In August 2018, the FASB issued ASU 2018-13, Fair Value Measurement (Topic 820) - Disclosure Framework - Changes to the Disclosure Requirements for Fair Value Measurement. The amendment modifies, removes, and adds certain disclosure requirements on fair value measurements. The ASU is effective for annual periods, including interim periods within those annual periods, beginning after December 15, 2019. The amendments on changes in unrealized gains and losses, the range and weighted average of significant unobservable inputs used to develop Level 3 fair value measurements, and the narrative description of measurement uncertainty should be applied prospectively for only the most recent interim or annual period presented in the initial fiscal year of adoption. All other amendments should be applied retrospectively to all periods presented upon their effective date. Early adoption is permitted. The Company is currently evaluating the impact adoption of the standard on the consolidated financial statements.

In August 2018, the FASB issued ASU 2018-15, Intangibles - Goodwill and Other - Internal-Use Software (Subtopic 350-40) - Customer’s Accounting for Implementation Costs Incurred in a Cloud Computing Arrangement that is a Service Contract. The amendment aligns the requirements for capitalizing implementation costs incurred in a hosting arrangement that is a service contract with the requirements for capitalizing implementation costs incurred to develop or obtain internal-use software (and hosting arrangements that include an internal use software license). The accounting for the service element of a hosting arrangement that is a service contract is not affected by the amendment. The ASU is effective for annual periods, including interim periods within those annual periods, beginning after December 15, 2019. Early adoption is permitted. The Company is currently evaluating the impact of adoption of the standard on the consolidated financial statements.

Reclassifications

f.Reclassifications

Certain reclassifications have been made to prior year amounts to conform to the current year presentation.

Revenue Recognition

The Company generates revenue primarily through the sale and delivery of promised goods or services to customers and recognizes revenue when control is transferred to customers, in an amount that reflects the consideration the Company expects to be entitled to in exchange for the goods or services. Sales prices are documented in the executed sales contract or purchase order prior to the transfer of control to the customer. Customers may enter into a separate extended service agreement to purchase an extended warranty for miraDry products from the Company whereby the payment is due at the inception of the agreement. Revenue for extended service agreements are recognized ratably over the term of the agreements.

The Company introduced its Platinum20 Limited Warranty Program, or Platinum20, in May 2018 on all OPUS breast implants implanted in the United States or Puerto Rico on or after May 1, 2018. Platinum20 provides for financial assistance for revision surgeries and no-charge contralateral replacement implants upon the occurrence of certain qualifying events. The Company considers Platinum20 to have an assurance warranty component and a service warranty component. The assurance component is recorded as a warranty liability at the time of sale (as discussed in Note 7). The Company considers the service warranty component as an additional performance obligation and defers revenue at the time of sale by estimating a standalone selling price using the expected cost plus margin approach for each performance obligation. The Company recognizes the revenue once all performance obligations have been met. The liability for the service warranty as of September 30, 2018 was $0.2 million, of which $0.1 million is considered a short-term obligation and is included in “accrued and other current liabilities” and $0.1 million is considered a long-term obligation and is included in “warranty reserve and other long-term liabilities” on the condensed consolidated balance sheet. The performance obligation is satisfied at the time that Platinum20 benefits are provided and are expected to be satisfied over the following two years for financial assistance and 20 years for product replacement. Revenue recognized for the service warranty performance obligations for the three and nine months ended September 30, 2018 was immaterial.

The Company also leverages a distributor network for selling the miraDry System internationally. The Company recognizes revenue when control of the goods or services is transferred to the distributors. Standard terms in these agreements do not allow for trial periods, right of return, refunds, rebates, payment contingent on obtaining financing or other terms that could impact the customer’s payment obligation. Contract liabilities are included in “accrued and other current liabilities” in the condensed consolidated balance sheet.

A portion of the Company’s revenue is generated from the sale of consigned inventory of breast implants maintained at doctor, hospital, and clinic locations. For these products, revenue is recognized at the time the Company is notified by the customer that the product has been implanted, not when the consigned products are delivered to the customer’s location.

For Breast Products, with the exception of the Company’s BIOCORNEUM scar management products, the Company allows for the return of products from customers within six months after the original sale, which is accounted for as variable consideration. Reserves are established for anticipated sales returns based on the expected amount calculated with historical experience, recent gross sales and any notification of pending returns. The estimated sales return is recorded as a reduction of revenue and as a sales return liability in the same period revenue is recognized. Actual sales returns in any future period are inherently uncertain and thus may differ from the estimates. If actual sales returns differ significantly from the estimates, an adjustment to revenue in the current or subsequent period would be recorded. The Company has established an allowance for sales returns of $5.3 million and $3.9 million as of September 30, 2018 and December 31, 2017, respectively, recorded as “sales return liability” on the condensed consolidated balance sheet under Topic 606 as of September 30, 2018 and recorded in “accounts receivable, net of allowances,” at December 31, 2017 on the condensed consolidated balance sheet, as indicated above in “Recently Adopted Accounting Standards.”

Sales tax, value-added tax, and other taxes the Company may collect concurrent with revenue-producing activities are excluded from the measurement of the transaction price and thus from revenue.

Summary of Significant Accounting Policies (Tables)

9 Months Ended

Sep. 30, 2018

ASU 2014-09

New Accounting Pronouncements Or Change In Accounting Principle [Line Items]

Schedule of Impact of Topic 606 Adoption on the Company's Condensed Consolidated Balance Sheet

In accordance with Topic 606 disclosure requirements, the impact of adoption on the Company’s condensed consolidated balance sheet was as follows (in thousands):



	As Reported		Total		Adjusted
	December 31, 2017		Adjustment		January 1, 2018
Balance Sheet
Assets
Accounts receivable, net of allowances	$	6,569		3,906		10,475
Liabilities
Sales return liability	$	—		3,906		3,906



	As Reported		Total			Amounts Under
	September 30, 2018		Adjustment			Previous Standards
Balance Sheet
Assets
Accounts receivable, net of allowances	$	18,956		(5,335	)		13,621
Liabilities
Sales return liability	$	5,335		(5,335	)		—

Acquisitions (Tables) - miraDry

9 Months Ended

Sep. 30, 2018

Business Acquisition [Line Items]

Schedule of aggregate acquisition date fair value of consideration transferred

The aggregate acquisition date fair value of the consideration transferred was approximately $29.6 million, consisting of the following (in thousands):

	Fair Value
Cash consideration at Acquisition Date (other than debt payoff)	$	6,193
Cash consideration at Acquisition Date (debt payoff)		12,467
Deferred consideration		966
Contingent consideration		9,946
Total purchase consideration	$	29,572

Schedule of allocation of the fair value of the consideration transferred by major class

In accordance with ASC 805, the Company has recorded the acquired assets (including identifiable intangible assets) and liabilities assumed at their respective fair value. The allocation of the total purchase price is as follows (in thousands):

	July 25,
	2017
Cash	$	205
Accounts receivable, net		2,091
Inventories, net		7,064
Other current assets		170
Property and equipment, net		528
Goodwill		7,629
Intangible assets		14,800
Restricted cash		305
Other assets		12
Liabilities assumed:
Accounts payable		(908	)
Accrued and other current liabilities		(2,294	)
Other current liabilities		(30	)
Net assets acquired	$	29,572

Schedule of intangible assets acquired

A summary of the intangible assets acquired, estimated useful lives and amortization methods is as follows (in thousands):

			Estimated useful	Amortization
	Amount		life	method
Developed technology	$	3,000	15 years	Accelerated
Customer relationships		6,300	14 years	Accelerated
Distributor relationships		500	9 years	Accelerated
Trade name		5,000	15 years	Accelerated
	$	14,800

Unaudited Pro Forma Information

The pro forma data are for informational purposes only and are not necessarily indicative of the condensed consolidated results of operations of the combined business had the merger actually occurred at the beginning of fiscal year 2017 or of the results of future operations of the combined business. Consequently, actual results will differ from the unaudited pro forma information presented below (in thousands, except per share amounts):

	Three Months Ended			Nine Months Ended
	September 30,			September 30,
	2017			2017
	Pro Forma			Pro Forma
Net sales	$	10,668		$	35,681
Net loss		(11,960	)		(56,053	)
Pro forma loss per share attributable to ordinary shares - basic and diluted	$	(0.62	)	$	(2.95	)

Fair Value Measurements (Tables)

9 Months Ended

Sep. 30, 2018

Fair Value Disclosures [Abstract]

Schedule of Company's liabilities that are measured at fair value on a recurring basis

The following tables present information about the Company’s liabilities that are measured at fair value on a recurring basis as of September 30, 2018 and December 31, 2017 and indicate the level of the fair value hierarchy utilized to determine such fair value (in thousands):

	Fair Value Measurements as of
	September 30, 2018 Using:
	Level 1		Level 2		Level 3		Total
Liabilities:
Liability for common stock warrants	$	—		—		527		527
Liability for contingent consideration		—		—		14,497		14,497
	$	—		—		15,024		15,024

	Fair Value Measurements as of
	December 31, 2017 Using:
	Level 1		Level 2		Level 3		Total
Liabilities:
Liability for common stock warrants	$	—		—		194		194
Liability for contingent consideration		—		—		12,319		12,319
	$	—		—		12,513		12,513

Schedule of aggregate fair values of the Company's common stock warrants and contingent consideration for which fair value is determined by Level 3 inputs

The following table provides a rollforward of the aggregate fair values of the Company’s common stock warrants and contingent consideration for which fair value is determined by Level 3 inputs (in thousands):

Warrant Liability
Balance, December 31, 2017	$	194
Change in fair value of warrant liability		333
Balance, September 30, 2018	$	527
Contingent Consideration Liability
Balance, December 31, 2017	$	12,319
Change in fair value of contingent consideration		2,178
Balance, September 30, 2018	$	14,497

Product Warranties (Tables)

9 Months Ended

Sep. 30, 2018

Product Warranties Disclosures [Abstract]

Schedule of rollforward of the accrued warranties

The following table provides a rollforward of the accrued warranties (in thousands):

	Nine Months Ended September 30,
	2018			2017
Beginning balance as of January 1	$	1,642		$	1,378
Acquired warranty liability		—			137
Warranty costs incurred during the period		(395	)		(11	)
Changes in accrual related to warranties issued during the period		639			125
Changes in accrual related to pre-existing warranties		(637	)		8
Balance as of September 30	$	1,249		$	1,637

Net Loss Per Share (Tables)

9 Months Ended

Sep. 30, 2018

Earnings Per Share [Abstract]

Schedule of net loss per share, basic and diluted

	Three Months Ended September 30,						Nine Months Ended September 30,
	2018			2017			2018			2017
Net loss (in thousands)	$	(20,545	)	$	(14,381	)	$	(57,996	)	$	(46,192	)
Weighted average common shares outstanding, basic and diluted		28,462,975			19,328,244			24,312,300			19,079,788
Net loss per share attributable to common stockholders	$	(0.72	)	$	(0.74	)	$	(2.39	)	$	(2.42	)

Schedule of potentially dilutive securities excluded from the computation of diluted net loss per share attributable to common stockholders

The Company excluded the following potentially dilutive securities, outstanding as of September 30, 2018 and 2017, from the computation of diluted net loss per share attributable to common stockholders for the three and nine months ended September 30, 2018 and 2017 because they had an anti-dilutive impact due to the net loss attributable to common stockholders incurred for the periods.

	September 30,
	2018		2017
Stock options to purchase common stock		1,926,835		1,872,999
Warrants for the purchase of common stock		47,710		47,710
		1,974,545		1,920,709

Balance Sheet Components (Tables)

9 Months Ended

Sep. 30, 2018

Balance Sheet Related Disclosures [Abstract]

Schedule of inventories, net

Inventories, net consist of the following (in thousands):

	September 30,		December 31,
	2018		2017
Raw materials	$	1,946	$	1,642
Work in progress		1,806		3,956
Finished goods		17,805		15,298
Finished goods - right of return		1,352		—
	$	22,909	$	20,896

Schedule of prepaid expenses and other current assets

c.

Prepaid Expenses and Other Current Assets

Prepaid expenses and other current assets consist of the following (in thousands):

	September 30,		December 31,
	2018		2017
Prepaid expenses	$	2,370	$	1,040
Other current assets		1,112		472
Total	$	3,482	$	1,512

Schedule of property and equipment, net

Property and equipment, net consist of the following (in thousands):

	September 30,			December 31,
	2018			2017
Leasehold improvements	$	402		$	402
Manufacturing equipment and toolings		1,809			4,260
Computer equipment		478			387
Software		1,023			797
Office equipment		156			142
Furniture and fixtures		820			816
		4,688			6,804
Less accumulated depreciation		(2,248	)		(2,041	)
	$	2,440		$	4,763

Schedule of changes in carrying amount of goodwill

The changes in the carrying amount of goodwill during the nine months ended September 30, 2018 were as follows (in thousands):

	Breast Products			miraDry		Total
Balances as of December 31, 2017
Goodwill	$	19,156		$	7,629	$	26,785
Accumulated impairment losses		(14,278	)		—		(14,278	)
Goodwill, net	$	4,878		$	7,629	$	12,507

Balances as of September 30, 2018
Goodwill	$	19,156		$	7,629	$	26,785
Accumulated impairment losses		(14,278	)		—		(14,278	)
Goodwill, net	$	4,878		$	7,629	$	12,507

Schedule of intangible assets

The components of the Company’s other intangible assets consist of the following (in thousands):

	Average
	Amortization		September 30, 2018
	Period		Gross Carrying		Accumulated			Intangible
	(in years)		Amount		Amortization			Assets, net
Intangibles with definite lives
Customer relationships		11	$	11,240	$	(3,078	)	$	8,162
Trade names - finite life		14		5,800		(460	)		5,340
Developed technology		15		3,000		(277	)		2,723
Distributor relationships		9		500		(108	)		392
Non-compete agreement		2		80		(78	)		2
Regulatory approvals		1		670		(670	)		—
Acquired FDA non-gel product approval		11		1,713		(1,713	)		—
Total definite-lived intangible assets			$	23,003	$	(6,384	)	$	16,619

Intangibles with indefinite lives
Trade names - indefinite life	—			450		—			450
Total indefinite-lived intangible assets			$	450	$	—		$	450

	Average
	Amortization		December 31, 2017
	Period		Gross Carrying		Accumulated			Intangible
	(in years)		Amount		Amortization			Assets, net
Intangibles with definite lives
Customer relationships		11	$	11,240	$	(1,859	)	$	9,381
Trade names - finite life		14		5,800		(216	)		5,584
Developed technology		15		3,000		(95	)		2,905
Distributor relationships		9		500		(40	)		460
Non-compete agreement		2		80		(57	)		23
Regulatory approvals		1		670		(670	)		—
Acquired FDA non-gel product approval		11		1,713		(1,713	)		—
Total definite-lived intangible assets			$	23,003	$	(4,650	)	$	18,353

Intangibles with indefinite lives
Trade names - indefinite life	—			450		—			450
Total indefinite-lived intangible assets			$	450	$	—		$	450

Schedule of estimated amortization expense

The following table summarizes the estimated amortization expense relating to the Company's definite-lived intangible assets as of September 30, 2018 (in thousands):

	Amortization
Period	Expense
Remainder of 2018	$	574
2019		2,321
2020		2,209
2021		1,996
2022		1,762
Thereafter		7,757
	$	16,619

Schedule of accrued and other current liabilities

Accrued and other current liabilities consist of the following (in thousands):

	September 30,		December 31,
	2018		2017
Payroll and related expenses	$	6,818	$	3,579
Accrued commissions		2,978		3,297
Accrued equipment		200		1,091
Deferred and contingent consideration, current portion		8,440		977
Audit, consulting and legal fees		768		920
Accrued sales and marketing expenses		1,255		794
Other		4,759		2,816
	$	25,218	$	13,474

Long-Term Debt and Revolving Loan (Tables)

9 Months Ended

Sep. 30, 2018

Debt Disclosure [Abstract]

Schedule of Future Principal Payments for Outstanding Term Loans

The future schedule of principal payments for the outstanding Term Loans as of September 30, 2018 was as follows (in thousands):

Fiscal Year
2019	$	7,000
2020		14,000
2021		14,000
2022		—
2023		—
Thereafter		—
Total	$	35,000

Stockholders' Equity (Tables)

9 Months Ended

Sep. 30, 2018

Disclosure Of Compensation Related Costs Sharebased Payments [Abstract]

Summary of option activity

				Weighted		Weighted average
				average		remaining
	Option			exercise		contractual
	Shares			price		term (year)
Balances at December 31, 2017		2,179,787		$	7.60		7.27
Exercised		(147,463	)		7.79
Forfeited		(77,341	)		11.44
Balances at September 30, 2018		1,954,983		$	7.43		6.56

Summary of RSUs activity

				Weighted average
	Number			grant date
	of shares			fair value
Balances at December 31, 2017		928,552		$	9.12
Granted		1,738,940			13.98
Vested		(464,507	)		10.18
Forfeited		(154,112	)		11.23
Balances at September 30, 2018		2,048,873		$	12.84

Segment Information (Tables)

9 Months Ended

Sep. 30, 2018

Segment Reporting [Abstract]

Summary of Net Sales, Net Operating Loss and Net Assets by Reportable Segment

The following tables present the net sales, net operating loss and net assets by reportable segment for the periods presented (in thousands):

	Three Months Ended				Nine Months Ended
	September 30,				September 30,
	2018		2017		2018		2017
Net sales
Breast Products	$	8,613	$	7,655	$	26,566	$	23,313
miraDry		8,262		2,164		22,538		2,164
Total net sales	$	16,875	$	9,819	$	49,104	$	25,477

	Three Months Ended				Nine Months Ended
	September 30,				September 30,
	2018		2017		2018		2017
Loss from operations
Breast Products	$	13,873	$	11,253	$	39,111	$	42,878
miraDry		5,689		2,602		16,278		2,602
Total loss from operations	$	19,562	$	13,855	$	55,389	$	45,480

	September 30,		December 31,
	2018		2017
Assets
Breast Products	$	144,333	$	59,365
miraDry		36,747		32,848
Total assets	$	181,080	$	92,213

Formation and Business of the Company (Details)			9 Months Ended
Formation and Business of the Company (Details)	May 07, 2018 USD ($) $ / shares shares	Jun. 11, 2017 USD ($) Payment $ / shares	Sep. 30, 2018
Formation and Business of the Company [Line Items]
Proceeds from the issuance of common stock, net of underwriting discounts, commissions and offering expenses	$ 107,600,000
Underwritten Follow-On Offering \| Common stock
Formation and Business of the Company [Line Items]
Shares issued in follow-on public offering \| shares	7,407,408
Public offering price (in dollars per share) \| $ / shares	$ 13.50
Additional shares granted to underwriters \| shares	1,111,111
Proceeds from the issuance of common stock, net of underwriting discounts, commissions and offering expenses	$ 107,600,000
Payment of underwriting discounts and commissions and offering expenses	6,900,000
Offering expenses	$ 500,000
miraDry
Formation and Business of the Company [Line Items]
Business acquisition agreement date			Jun. 11, 2017
Business purchase price per share \| $ / shares		$ 0.3149
Business combination, upfront cash payments		$ 18,700,000
Business combination, potential contingent payments		$ 9,946,000
Effective date of acquisition			Jul. 25, 2017
Minimum \| miraDry
Formation and Business of the Company [Line Items]
Number of contingent payments \| Payment		1
Maximum \| miraDry
Formation and Business of the Company [Line Items]
Business combination, potential contingent payments		$ 14,000,000

Summary of Significant Accounting Policies (Details) - USD ($) $ in Thousands		1 Months Ended
	May 07, 2018	Feb. 28, 2018	Sep. 30, 2018	Apr. 30, 2018	Apr. 17, 2018	Dec. 31, 2017
Summary Of Significant Accounting Policies [Line Items]
Cash and cash equivalents			$ 103,008			$ 26,588
Common stock, shares issued			28,650,944			19,474,702
Proceeds from the issuance of common stock, net of underwriting discounts, commissions and offering expenses	$ 107,600
At-The-Market Equity Offering Sales Agreement
Summary Of Significant Accounting Policies [Line Items]
Common stock, shares issued			0
Maximum
Summary Of Significant Accounting Policies [Line Items]
Aggregate gross offering price		$ 50,000
March Two Thousand Eighteen Term Loan
Summary Of Significant Accounting Policies [Line Items]
Loan amount outstanding				$ 10,000	$ 10,000

- Definition

The carrying value as of the balance sheet date of the current and noncurrent portions of long-term obligations drawn from a line of credit, which is a bank's commitment to make loans up to a specific amount. Examples of items that might be included in the application of this element may consist of letters of credit, standby letters of credit, and revolving credit arrangements, under which borrowings can be made up to a maximum amount as of any point in time conditional on satisfaction of specified terms before, as of and after the date of drawdowns on the line. Includes short-term obligations that would normally be classified as current liabilities but for which (a) postbalance sheet date issuance of a long term obligation to refinance the short term obligation on a long term basis, or (b) the enterprise has entered into a financing agreement that clearly permits the enterprise to refinance the short-term obligation on a long term basis and the following conditions are met (1) the agreement does not expire within 1 year and is not cancelable by the lender except for violation of an objectively determinable provision, (2) no violation exists at the BS date, and (3) the lender has entered into the financing agreement is expected to be financially capable of honoring the agreement.

+ References + Details

Summary of Significant Accounting Policies - Schedule of Impact of Topic 606 Adoption on the Company's Condensed Consolidated Balance Sheet (Details) - USD ($) $ in Thousands	Sep. 30, 2018	Jan. 01, 2018	Dec. 31, 2017
Assets
Accounts receivable, net of allowances	$ 18,956		$ 6,569
Liabilities
Sales return liability	5,335
ASU 2014-09
Assets
Accounts receivable, net of allowances		$ 10,475
Liabilities
Sales return liability		3,906
Total Adjustment \| ASU 2014-09
Assets
Accounts receivable, net of allowances	(5,335)	3,906
Liabilities
Sales return liability	(5,335)	$ 3,906
Amounts Under Previous Standards \| ASU 2014-09
Assets
Accounts receivable, net of allowances	$ 13,621

Revenue (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended		12 Months Ended
Revenue (Details) - USD ($) $ in Thousands	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017	Dec. 31, 2017
Revenue From Contracts With Customers [Line Items]
Liability for service warranty	$ 200		$ 200
Period for sales return			6 months
Allowance for sales returns			$ 5,300		$ 3,900
Revenue, practical expedient, incremental cost of obtaining contract			true
Revenue, practical expedient, significant financing component			true
Shipping and handling costs	6,398	$ 3,484	$ 19,154	$ 8,427
Breast Products \| Sales and marketing expense
Revenue From Contracts With Customers [Line Items]
Shipping and handling costs	$ 300	$ 200	$ 900	$ 700
Type of Cost, Good or Service [Extensible List]	us-gaap:ShippingAndHandlingMember	us-gaap:ShippingAndHandlingMember	us-gaap:ShippingAndHandlingMember	us-gaap:ShippingAndHandlingMember
miraDry \| Cost of goods sold
Revenue From Contracts With Customers [Line Items]
Shipping and handling costs	$ 100		$ 200
Type of Cost, Good or Service [Extensible List]	us-gaap:ShippingAndHandlingMember		us-gaap:ShippingAndHandlingMember
Financial Assistance
Revenue From Contracts With Customers [Line Items]
Performance obligation satisfing period	2 years		2 years
Product Replacement
Revenue From Contracts With Customers [Line Items]
Performance obligation satisfing period	20 years		20 years
Accrued and Other Current Liabilities
Revenue From Contracts With Customers [Line Items]
Short-term obligation	$ 100		$ 100
Warranty Reserve and Other Long-term Liabilities
Revenue From Contracts With Customers [Line Items]
Long-term obligation	$ 100		$ 100

Acquisitions (Details)		3 Months Ended		9 Months Ended
Acquisitions (Details)	Jun. 11, 2017 USD ($) Payment $ / shares	Sep. 30, 2018 USD ($)	Sep. 30, 2017 USD ($)	Sep. 30, 2018 USD ($)	Sep. 30, 2017 USD ($)	Dec. 31, 2017 USD ($)
Business Acquisition [Line Items]
Legal settlement payable		$ 410,000		$ 410,000		$ 1,000,000
Legal settlement					$ 10,000,000
miraDry
Business Acquisition [Line Items]
Business acquisition agreement date				Jun. 11, 2017
Business purchase price per share \| $ / shares	$ 0.3149
Cash	$ 18,700,000
Contingent consideration	9,946,000
Effective date of acquisition				Jul. 25, 2017
Professional fees		0	$ 2,600,000	$ 0	$ 3,000,000
Fair value of consideration transferred	$ 29,572,000
Legal settlement payable		$ 400,000		400,000
Legal settlement				$ 600,000
Business combination contingent consideration payment period	1 year
miraDry \| Minimum
Business Acquisition [Line Items]
Number of contingent payments \| Payment	1
miraDry \| Maximum
Business Acquisition [Line Items]
Contingent consideration	$ 14,000,000
Estimated future payments due	$ 14,000,000

Acquisitions - Schedule of aggregate acquisition date fair value of consideration transferred (Details) - miraDry $ in Thousands	Jun. 11, 2017 USD ($)
Business Acquisition [Line Items]
Cash consideration at Acquisition Date (other than debt payoff)	$ 6,193
Cash consideration at Acquisition Date (debt payoff)	12,467
Deferred consideration	966
Contingent consideration	9,946
Total purchase consideration	$ 29,572

Acquisitions - Schedule of allocation of the fair value of the consideration transferred by major class (Details) - USD ($) $ in Thousands	Sep. 30, 2018	Dec. 31, 2017	Jul. 25, 2017
Fair value of the assets acquired
Goodwill	$ 12,507	$ 12,507
miraDry
Fair value of the assets acquired
Cash			$ 205
Accounts receivable, net			2,091
Inventories, net			7,064
Other current assets			170
Property and equipment, net			528
Goodwill			7,629
Intangible assets			14,800
Restricted cash			305
Other assets			12
Liabilities assumed:
Accounts payable			(908)
Accrued and other current liabilities			(2,294)
Other current liabilities			(30)
Net assets acquired			$ 29,572

Acquisitions - Schedule of intangible assets acquired (Details) - miraDry $ in Thousands	Jul. 25, 2017 USD ($)
Fair value of the assets acquired
Intangible assets	$ 14,800
Developed technology
Fair value of the assets acquired
Intangible assets	$ 3,000
Estimated useful life of asset	15 years
Amortization method	Accelerated
Customer relationships
Fair value of the assets acquired
Intangible assets	$ 6,300
Estimated useful life of asset	14 years
Amortization method	Accelerated
Distributor relationships
Fair value of the assets acquired
Intangible assets	$ 500
Estimated useful life of asset	9 years
Amortization method	Accelerated
Trade name
Fair value of the assets acquired
Intangible assets	$ 5,000
Estimated useful life of asset	15 years
Amortization method	Accelerated

Acquisitions - Unaudited Pro Forma Information (Details) - miraDry - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended	9 Months Ended
	Sep. 30, 2017	Sep. 30, 2017
Business Acquisition [Line Items]
Net sales	$ 10,668	$ 35,681
Net loss	$ (11,960)	$ (56,053)
Pro forma loss per share attributable to ordinary shares - basic and diluted	$ (0.62)	$ (2.95)

Fair Value Measurements (Details)	Sep. 30, 2018
Estimated Dividend Yield
Fair Value Measurements
Measurement input	0.00

Fair Value Measurements - Schedule of Company's liabilities that are measured at fair value on a recurring basis (Details) - Recurring - USD ($) $ in Thousands	Sep. 30, 2018	Dec. 31, 2017
Fair Value Measurements
Fair value liability	$ 15,024	$ 12,513
Warrants
Fair Value Measurements
Fair value liability	527	194
Contingent Consideration Liability
Fair Value Measurements
Fair value liability	14,497	12,319
Level 3
Fair Value Measurements
Fair value liability	15,024	12,513
Level 3 \| Warrants
Fair Value Measurements
Fair value liability	527	194
Level 3 \| Contingent Consideration Liability
Fair Value Measurements
Fair value liability	$ 14,497	$ 12,319

Fair Value Measurements - Schedule of aggregate fair values of the Company's common stock warrants and contingent consideration for which fair value is determined by Level 3 inputs (Details) - Level 3 - Recurring $ in Thousands	9 Months Ended
	Sep. 30, 2018 USD ($)
Warrants
Fair values of the Company's liabilities determined by Level 3 inputs
Balance at beginning of the period	$ 194
Change in fair value	333
Balance at the end of the period	527
Contingent Consideration Liability
Fair values of the Company's liabilities determined by Level 3 inputs
Balance at beginning of the period	12,319
Change in fair value	2,178
Balance at the end of the period	$ 14,497

Product Warranties (Details) - USD ($)	9 Months Ended
Product Warranties (Details) - USD ($)	Sep. 30, 2018	Dec. 31, 2017	Sep. 30, 2017	Dec. 31, 2016
Product Warranty Liability [Line Items]
Replacement implants and revision surgery financial assistance under limited warranty program	$ 1,249,000	$ 1,642,000	$ 1,637,000	$ 1,378,000
Implants occurring prior to May 1, 2018
Product Warranty Liability [Line Items]
Period to claim financial assistance under limited warranty program	10 years
Implants occurring prior to May 1, 2018 \| Maximum
Product Warranty Liability [Line Items]
Replacement implants and revision surgery financial assistance under limited warranty program	$ 3,600
Implants occurring on or after May 1, 2018
Product Warranty Liability [Line Items]
Period to claim financial assistance under limited warranty program	20 years
Implants occurring on or after May 1, 2018 \| Maximum
Product Warranty Liability [Line Items]
Replacement implants and revision surgery financial assistance under limited warranty program	$ 5,000

Product Warranties - Schedule of rollforward of the accrued warranties (Details) - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017
Product Warranties Disclosures [Abstract]
Beginning balance	$ 1,642	$ 1,378
Acquired warranty liability		137
Warranty costs incurred during the period	(395)	(11)
Changes in accrual related to warranties issued during the period	639	125
Changes in accrual related to pre-existing warranties	(637)	8
Ending Balance	$ 1,249	$ 1,637

Net Loss Per Share - Schedule of Net Loss Per Share, Basic and Diluted (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
Earnings Per Share [Abstract]
Net loss	$ (20,545)	$ (14,381)	$ (57,996)	$ (46,192)
Weighted average common shares outstanding, basic and diluted	28,462,975	19,328,244	24,312,300	19,079,788
Net loss per share attributable to common stockholders	$ (0.72)	$ (0.74)	$ (2.39)	$ (2.42)

- Definition

The portion of profit or loss for the period, net of income taxes, which is attributable to the parent.

+ References + Details

Net Loss Per Share - Schedule of Potentially Dilutive Securities Excluded from Computation of Diluted Net Loss Per Share Attributable to Common Stockholders (Details) - shares	9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017
Potentially dilutive securities
Potentially dilutive securities	1,974,545	1,920,709
Stock options to purchase common stock
Potentially dilutive securities
Potentially dilutive securities	1,926,835	1,872,999
Warrants for the purchase of common stock
Potentially dilutive securities
Potentially dilutive securities	47,710	47,710

Balance Sheet Components (Allowance) (Details) - USD ($) $ in Millions	Sep. 30, 2018	Dec. 31, 2017
Balance Sheet Related Disclosures [Abstract]
Allowance for doubtful accounts	$ 1.4	$ 0.9

Balance Sheet Components (Inventories) (Details) - USD ($) $ in Thousands	Sep. 30, 2018	Dec. 31, 2017
Balance Sheet Related Disclosures [Abstract]
Raw materials	$ 1,946	$ 1,642
Work in progress	1,806	3,956
Finished goods	17,805	15,298
Finished goods - right of return	1,352
Inventory, net	$ 22,909	$ 20,896

Balance Sheet Components (Prepaid Expenses and Other Current Assets) (Details) - USD ($) $ in Thousands	Sep. 30, 2018	Dec. 31, 2017
Balance Sheet Related Disclosures [Abstract]
Prepaid expenses	$ 2,370	$ 1,040
Other current assets	1,112	472
Total	3,482	$ 1,512
Repurchase equipment	$ 2,700

Balance Sheet Components (PPE) (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017	Dec. 31, 2017
Property Plant And Equipment [Line Items]
Property and equipment, gross	$ 4,688		$ 4,688		$ 6,804
Less accumulated depreciation	(2,248)		(2,248)		(2,041)
Property and equipment, net	2,440		2,440		4,763
Depreciation expense	200	$ 200	900	$ 600
Leasehold improvements
Property Plant And Equipment [Line Items]
Property and equipment, gross	402		402		402
Manufacturing equipment and toolings
Property Plant And Equipment [Line Items]
Property and equipment, gross	1,809		1,809		4,260
Computer equipment
Property Plant And Equipment [Line Items]
Property and equipment, gross	478		478		387
Software
Property Plant And Equipment [Line Items]
Property and equipment, gross	1,023		1,023		797
Office equipment
Property Plant And Equipment [Line Items]
Property and equipment, gross	156		156		142
Furniture and fixtures
Property Plant And Equipment [Line Items]
Property and equipment, gross	$ 820		$ 820		$ 816

Balance Sheet Components (Goodwill and Intangibles) (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended		12 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017	Dec. 31, 2017
Goodwill and intangible assets
Goodwill	$ 26,785		$ 26,785		$ 26,785
Accumulated impairment losses	(14,278)		(14,278)		(14,278)
Goodwill, net	12,507		12,507		12,507
Other intangible assets
Gross Carrying Amount	23,003		23,003		23,003
Accumulated Amortization	(6,384)		(6,384)		(4,650)
Intangible Assets, net	16,619		16,619		18,353
Indefinite-lived intangible assets	450		450		450
Amortization expense	600	$ 1,000	1,700	$ 1,800
Estimated amortization expense
Remainder of 2018	574		574
2019	2,321		2,321
2020	2,209		2,209
2021	1,996		1,996
2022	1,762		1,762
Thereafter	7,757		7,757
Total amortization	16,619		16,619
Trade name
Other intangible assets
Indefinite-lived intangible assets	450		$ 450		$ 450
Acquired FDA non-gel product approval
Other intangible assets
Average Amortization Period			11 years		11 years
Gross Carrying Amount	1,713		$ 1,713		$ 1,713
Accumulated Amortization	(1,713)		$ (1,713)		$ (1,713)
Customer relationships
Other intangible assets
Average Amortization Period			11 years		11 years
Gross Carrying Amount	11,240		$ 11,240		$ 11,240
Accumulated Amortization	(3,078)		(3,078)		(1,859)
Intangible Assets, net	8,162		$ 8,162		$ 9,381
Trade name
Other intangible assets
Average Amortization Period			14 years		14 years
Gross Carrying Amount	5,800		$ 5,800		$ 5,800
Accumulated Amortization	(460)		(460)		(216)
Intangible Assets, net	5,340		$ 5,340		$ 5,584
Developed technology
Other intangible assets
Average Amortization Period			15 years		15 years
Gross Carrying Amount	3,000		$ 3,000		$ 3,000
Accumulated Amortization	(277)		(277)		(95)
Intangible Assets, net	2,723		$ 2,723		$ 2,905
Distributor relationships
Other intangible assets
Average Amortization Period			9 years		9 years
Gross Carrying Amount	500		$ 500		$ 500
Accumulated Amortization	(108)		(108)		(40)
Intangible Assets, net	392		$ 392		$ 460
Regulatory approvals
Other intangible assets
Average Amortization Period			1 year		1 year
Gross Carrying Amount	670		$ 670		$ 670
Accumulated Amortization	(670)		$ (670)		$ (670)
Non-compete agreement
Other intangible assets
Average Amortization Period			2 years		2 years
Gross Carrying Amount	80		$ 80		$ 80
Accumulated Amortization	(78)		(78)		(57)
Intangible Assets, net	2		2		23
Breast Products
Goodwill and intangible assets
Goodwill	19,156		19,156		19,156
Accumulated impairment losses	(14,278)		(14,278)		(14,278)
Goodwill, net	4,878		4,878		4,878
miraDry
Goodwill and intangible assets
Goodwill	7,629		7,629		7,629
Goodwill, net	$ 7,629		$ 7,629		$ 7,629

Balance Sheet Components (Accrued liabilities) (Details) - USD ($) $ in Thousands	Sep. 30, 2018	Dec. 31, 2017
Accrued and other current liabilities
Payroll and related expenses	$ 6,818	$ 3,579
Accrued commissions	2,978	3,297
Accrued equipment	200	1,091
Deferred and contingent consideration, current portion	8,440	977
Audit, consulting and legal fees	768	920
Accrued sales and marketing expenses	1,255	794
Other	4,759	2,816
Total	$ 25,218	$ 13,474

Long-Term Debt and Revolving Loan (Details) - USD ($)			3 Months Ended		9 Months Ended
Long-Term Debt and Revolving Loan (Details) - USD ($)	Apr. 18, 2018	Jul. 25, 2017	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017	Apr. 30, 2018	Apr. 17, 2018
Line Of Credit Facility [Line Items]
Credit and security agreement entered date		Jul. 25, 2017
Amortization of debt issuance costs			$ 47,000	$ 28,500	$ 100,000	$ 100,000
Additional interest (as a percent)		5.00%
Term Loan Credit Agreement
Line Of Credit Facility [Line Items]
Amount funded by Midcap under agreement		$ 25,000,000
Lines of credit facility available date	Apr. 30, 2018	Mar. 31, 2018
Loan amount outstanding		$ 40,000,000	35,000,000		35,000,000
Debt scheduled maturity date		Dec. 01, 2021
Origination fee (as a percent)		0.50%
Unamortized debt issuance costs on term loan, current portion			100,000		100,000
Unamortized debt issuance costs on term loan, long-term portion			100,000		$ 100,000
Term Loan Credit Agreement \| London Interbank Offered Rate (LIBOR)
Line Of Credit Facility [Line Items]
Spread on variable rate basis (as a percent)					7.50%
Debt Instrument Reference Rate					2.10%
Term Loan Credit Agreement \| Minimum \| London Interbank Offered Rate (LIBOR)
Line Of Credit Facility [Line Items]
Debt instrument, interest rate floor		1.00%
March Two Thousand Eighteen Term Loan
Line Of Credit Facility [Line Items]
Line of Credit Facility, Remaining Borrowing Capacity		$ 10,000,000
Loan amount outstanding							$ 10,000,000	$ 10,000,000
Additional Term Loan
Line Of Credit Facility [Line Items]
Line of Credit Facility, Remaining Borrowing Capacity		5,000,000
Minimum revenue required to satisfy additional term loan facility		75,000,000
Revolving Credit Agreement
Line Of Credit Facility [Line Items]
Loan amount outstanding		$ 10,000,000	0		$ 0
Borrowing base of accounts receivable (as a percent)		85.00%
Borrowing base of finished goods inventory (as a percent)		40.00%
Debt scheduled maturity date		Dec. 01, 2021
Origination fee (as a percent)		0.50%
Annual collateral management fee (as a percent)		0.50%
Annual unused line fee of average unused portion (as a percent)		0.50%
Revolving Credit Agreement \| Other Long-Term Assets
Line Of Credit Facility [Line Items]
Unamortized debt issuance costs on term loan, long-term portion			$ 100,000		$ 100,000
Revolving Credit Agreement \| London Interbank Offered Rate (LIBOR)
Line Of Credit Facility [Line Items]
Spread on variable rate basis (as a percent)		4.50%
Revolving Credit Agreement \| Maximum
Line Of Credit Facility [Line Items]
Borrowing base availability from finished goods inventory (as a percent)		20.00%
Revolving Credit Agreement \| Minimum \| London Interbank Offered Rate (LIBOR)
Line Of Credit Facility [Line Items]
Debt instrument, interest rate floor		1.00%

Long-Term Debt and Revolving Loan (Schedule of Future Principal Payments for Outstanding Term Loans) (Details) - Term Loans $ in Thousands	Sep. 30, 2018 USD ($)
Line Of Credit Facility [Line Items]
2019	$ 7,000
2020	14,000
2021	14,000
Total	$ 35,000

Stockholders' Equity (Details) - $ / shares	Sep. 30, 2018	Dec. 31, 2017
Stock other disclosures
Common and preferred stock, shares authorized	210,000,000	210,000,000
Common stock, shares authorized	200,000,000	200,000,000
Common stock, par value (in dollars per share)	$ 0.01	$ 0.01
Preferred stock, shares authorized	10,000,000	10,000,000
Preferred stock, par value (in dollars per share)	$ 0.01	$ 0.01
Preferred stock, shares issued	0	0
Preferred stock, shares outstanding	0	0

Stockholders' Equity (Warrants) (Details) - $ / shares		1 Months Ended
Stockholders' Equity (Warrants) (Details) - $ / shares	Jan. 17, 2013	Jun. 30, 2014	Sep. 30, 2018
Common Stock Warrants
Aggregate number of common shares to purchase			47,710
Oxford Finance, LLC
Common Stock Warrants
Exercise price (in dollars per share)	$ 14.671	$ 14.671
Tranche A, B and C loans \| Oxford Finance, LLC
Common Stock Warrants
Warrant term	7 years
Percentage of term loan amounts	3.00%
Tranche D term loan \| Oxford Finance, LLC
Common Stock Warrants
Warrant term		7 years
Percentage of term loan amounts		2.50%

Stockholders' Equity (Options) (Details) - USD ($) $ / shares in Units, $ in Millions	3 Months Ended		9 Months Ended		12 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017	Dec. 31, 2016	Nov. 03, 2014	Apr. 30, 2007
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Number of shares available for future grants	543,955		543,955
Stock options
Number of options
Balance at the beginning of period (in shares)				2,179,787
Options exercised (in shares)			(147,463)
Options forfeited (in shares)			(77,341)
Balance at the end of the period (in shares)	1,954,983		1,954,983		2,179,787
Weighted average exercise price
Balance at the beginning of period (in dollars per share)				$ 7.60
Options exercised (in dollars per share)			$ 7.79
Options forfeited (in dollars per share)			11.44
Balance at the end of period (in dollars per share)	$ 7.43		$ 7.43		$ 7.60
Additional information
Weighted average remaining contractual term			6 years 6 months 21 days		7 years 3 months 7 days
Stock-based compensation expense	$ 0.5	$ 0.5	$ 1.3	$ 1.6
Unrecognized compensation costs (in dollars)	$ 1.2		$ 1.2
Weighted average period over which unrecognized compensation costs are expected to be recognized			1 year 5 months 12 days
2007 Plan
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Common stock initially reserved for issuance (in shares)							1,690,448
2014 Plan
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Common stock initially reserved for issuance (in shares)						1,027,500
Number of shares available for future grants	132,719		132,719
Inducement Plan
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Number of shares available for future grants	91,306		91,306
Number of shares awarded			876,441
Grant period of stock awards			10 years
Number of additional years of requisite service period			3 years
Vesting period			1 year
Inducement Plan \| On the first anniversary
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Vesting percentage			25.00%
Inducement Plan \| Minimum
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Purchase price of awards expressed as a percentage of fair value of shares on the date of grant			100.00%
Percentage of possible payouts of the target award			0.00%
Inducement Plan \| Minimum \| Individual options
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Vesting percentage			25.00%
Inducement Plan \| Maximum
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Percentage of possible payouts of the target award			100.00%
2007 Plan and 2014 Plan \| Stock options
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Grant period of stock awards			10 years
2007 Plan and 2014 Plan \| Stock options \| Minimum
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Purchase price of awards expressed as a percentage of fair value of shares on the date of grant			100.00%
Percentage of voting power owned by shareholder	10.00%		10.00%
2007 Plan and 2014 Plan \| Stock options \| Maximum
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Purchase price of awards expressed as a percentage of fair value of shares on the date of grant			110.00%

Stockholders' Equity (Restricted Stock) (Details) - Restricted stock units - 2014 Plan - USD ($) $ / shares in Units, $ in Millions	3 Months Ended		9 Months Ended		12 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017	Dec. 31, 2017
Stockholders' Equity, other disclosures
Requisite service period, quarterly			4 years
Requisite service period, annually			3 years
Stock-based compensation expense	$ 3.8	$ 1.0	$ 8.4	$ 2.8
Unrecognized compensation costs (in dollars)	$ 23.8		$ 23.8
Weighted average period over which unrecognized compensation costs are expected to be recognized			2 years 3 months 29 days
Number of shares
Balance at beginning of the period			2,048,873	928,552	928,552
Granted					1,738,940
Vested					(464,507)
Forfeited					(154,112)
Balance at end of the period					2,048,873
Weighted average grant date fair value
Balance at beginning of the period			$ 12.84	$ 9.12	$ 9.12
Granted					13.98
Vested					10.18
Forfeited					11.23
Balance at end of the period					$ 12.84

Stockholders' Equity (Stock Purchase) (Details) - USD ($) $ / shares in Units, $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017	Oct. 31, 2014
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Number of shares available for future grants	543,955		543,955
2014 Employee Stock Purchase Plan
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Purchase period of offering			6 months
Rate of purchase price of stock on fair value (as a percent)			85.00%
Purchases under the award			145,616
Weighted Average purchase price	$ 6.82		$ 6.82
Stock-based compensation expense	$ 0.2	$ 0.1	$ 0.4	$ 0.3
2014 Employee Stock Purchase Plan \| Maximum
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Discount rate on the value of shares through payroll deductions (as a percent)			15.00%
Expiration period of each offering			27 months
Number of shares reserved for future issuance					255,500

Income Taxes (Details) - USD ($)	3 Months Ended		9 Months Ended
Income Taxes (Details) - USD ($)	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
Income Tax Disclosure [Abstract]
Tax expense	$ 0	$ 16,000	$ 0	$ 70,000

Segment Information (Details)	9 Months Ended
Segment Information (Details)	Sep. 30, 2018 USD ($) Segment
Segment Reporting [Abstract]
Number of reportable segments \| Segment	2
Segments unallocated expenses \| $	$ 0

Segment Information - Summary of Net Sales, Net Operating Loss and Net Assets by Reportable Segment (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017	Dec. 31, 2017
Segment Reporting Information [Line Items]
Total net sales	$ 16,875	$ 9,819	$ 49,104	$ 25,477
Total loss from operations	19,562	13,855	55,389	45,480
Total assets	181,080		181,080		$ 92,213
Breast Products
Segment Reporting Information [Line Items]
Total net sales	8,613	7,655	26,566	23,313
Total loss from operations	13,873	11,253	39,111	42,878
Total assets	144,333		144,333		59,365
miraDry
Segment Reporting Information [Line Items]
Total net sales	8,262	2,164	22,538	2,164
Total loss from operations	5,689	$ 2,602	16,278	$ 2,602
Total assets	$ 36,747		$ 36,747		$ 32,848

Commitments and Contingencies (Details)						3 Months Ended			9 Months Ended
Commitments and Contingencies (Details)	Jul. 29, 2018 USD ($)	Nov. 11, 2017 USD ($)	Sep. 07, 2017 USD ($)	Jul. 27, 2017 USD ($) USD_Per_Unit	Nov. 19, 2015 lawsuit	Sep. 30, 2018 USD ($)	Sep. 30, 2017 USD ($)	Mar. 31, 2017 USD ($)	Sep. 30, 2018 USD ($)	Sep. 30, 2017 USD ($)	Sep. 30, 2016 USD ($)	Dec. 31, 2017 USD ($)
Operating Leases
Rent expense						$ 300,000	$ 200,000		$ 900,000	$ 500,000
Contingencies
General and administrative						11,904,000	$ 9,298,000		31,419,000	23,753,000
Loss contingency paid						410,000			410,000			$ 1,000,000
Legal settlement										$ 10,000,000
Litigation settlement agreement, amount paid or to be paid			$ 9,000,000
Royalty payments on each of net sales per product \| USD_Per_Unit				12.5
Maximum
Contingencies
Royalty expense				$ 5,000,000
Class Action Lawsuits
Contingencies
Number of lawsuits filed \| lawsuit					3
General and administrative											$ 1,600,000
Contingency loss in period											10,900,000
Insurance recovery receivable											$ 9,400,000
Received in insurance proceeds								$ 9,300,000
Loss contingency paid								$ 10,900,000
miraDry Class Action Litigation
Contingencies
Loss contingency paid						$ 400,000			400,000
Amount of Defendants (and/or their indemnitors and/or insurers) agreed to pay settlement consideration		$ 400,000
Legal settlement									$ 600,000
Litigation Settlement in 2018
Contingencies
Litigation settlement agreement, amount paid or to be paid	$ 1,000,000
California \| Santa Barbara
Operating Leases
Lease expiration date									Feb. 29, 2020
California \| Santa Clara
Operating Leases
Lease expiration date									May 31, 2024

Subsequent Events - Additional Information (Details) $ in Millions		9 Months Ended
	Oct. 19, 2018 ft²	Sep. 30, 2018 USD ($)
Subsequent Event [Line Items]
Letters of credit outstanding, amount \| $		$ 0.3
Letter of credit expiration date		Sep. 30, 2024
Lease Amendment \| Subsequent Event
Subsequent Event [Line Items]
Combined area of leased office space \| ft²	29,256
Lease contract term	62 months
Lease expiration date	Jul. 31, 2024
Lease Amendment \| Landlord \| Subsequent Event
Subsequent Event [Line Items]
Lease agreement date	Oct. 19, 2018