Sientra (SIENQ) 10-K 13 Mar 18 2017 FY Annual report Financial data

Document and Entity Information

Document and Entity Information - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Mar. 09, 2018	Jun. 30, 2017
Document And Entity Information [Abstract]
Entity Registrant Name	Sientra, Inc.
Entity Central Index Key	1,551,693
Document Type	10-K
Document Period End Date	Dec. 31, 2017
Amendment Flag	false
Current Fiscal Year End Date	--12-31
Entity Well-known Seasoned Issuer	No
Entity Voluntary Filers	No
Entity Current Reporting Status	Yes
Entity Filer Category	Accelerated Filer
Entity Public Float			$ 108,772,000
Entity Common Stock, Shares Outstanding		19,643,517
Document Fiscal Year Focus	2,017
Document Fiscal Period Focus	FY
Trading Symbol	SIEN

Consolidated Balance Sheets

Consolidated Balance Sheets - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2016
Current assets:
Cash and cash equivalents	$ 26,588	$ 67,212
Accounts receivable, net of allowances of $4,816 and $4,329 at December 31, 2017 and December 31, 2016, respectively	6,569	3,082
Inventories, net	20,896	18,484
Insurance recovery receivable	39	9,375
Prepaid expenses and other current assets	1,473	1,852
Total current assets	55,565	100,005
Property and equipment, net	4,763	2,986
Goodwill	12,507	4,878
Other intangible assets, net	18,803	6,186
Other assets	575	228
Total assets	92,213	114,283
Current liabilities:
Current portion of long-term debt	24,639
Accounts payable	5,811	3,555
Accrued and other current liabilities	13,474	6,507
Legal settlement payable	1,000	10,900
Customer deposits	5,423	6,559
Total current liabilities	50,347	27,521
Deferred and contingent consideration	12,597	1,637
Warranty reserve and other long-term liabilities	1,646	1,508
Total liabilities	64,590	30,666
Commitments and contingencies (Note 11)
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 19,474,702 and 18,671,409 and outstanding 19,401,975 and 18,598,682 shares at December 31, 2017 and December 31, 2016 respectively	194	186
Additional paid-in capital	307,159	299,133
Treasury stock, at cost (72,727 shares at December 31, 2017 and December 31, 2016)	(260)	(260)
Accumulated deficit	(279,470)	(215,442)
Total stockholders’ equity	27,623	83,617
Total liabilities and stockholders’ equity	$ 92,213	$ 114,283

Consolidated Balance Sheets (Pa

Consolidated Balance Sheets (Parenthetical) - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2016
Statement Of Financial Position [Abstract]
Accounts receivable, allowances (in dollars)	$ 4,816	$ 4,329
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	19,474,702	18,671,409
Common stock, shares outstanding	19,401,975	18,598,682
Treasury stock, shares	72,727	72,727

Consolidated Statements of Oper

Consolidated Statements of Operations - USD ($)	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Income Statement [Abstract]
Net sales	$ 36,542,000	$ 20,734,000	$ 38,106,000
Cost of goods sold	14,171,000	6,880,000	10,654,000
Gross profit	22,371,000	13,854,000	27,452,000
Operating expenses:
Sales and marketing	33,911,000	20,607,000	25,762,000
Research and development	9,813,000	9,704,000	7,199,000
General and administrative	31,537,000	21,959,000	18,738,000
Legal settlement	10,000,000	1,618,000
Goodwill impairment			14,278,000
Total operating expenses	85,261,000	53,888,000	65,977,000
Loss from operations	(62,890,000)	(40,034,000)	(38,525,000)
Other income (expense), net:
Interest income	172,000	63,000	32,000
Interest expense	(1,232,000)	(98,000)	(3,097,000)
Other income (expense), net	(95,000)	(36,000)	360,000
Total other income (expense), net	(1,155,000)	(71,000)	(2,705,000)
Loss before income taxes	(64,045,000)	(40,105,000)	(41,230,000)
Income tax (benefit) expense	(17,000)	61,000	0
Net loss	$ (64,028,000)	$ (40,166,000)	$ (41,230,000)
Basic and diluted net loss per share attributable to common stockholders	$ (3.34)	$ (2.20)	$ (2.61)
Weighted average outstanding common shares used for net loss per share attributable to common stockholders:
Basic and diluted	19,159,057	18,233,177	15,770,972

Consolidated Statements of Stoc

Consolidated Statements of Stockholders' Equity - USD ($) $ in Thousands	Total	Common stock	Treasury stock	Additional paid-in capital	Accumulated deficit
Balance, beginning of year at Dec. 31, 2014	$ 95,639	$ 150	$ (260)	$ 229,795	$ (134,046)
Balance, beginning of year (in shares) at Dec. 31, 2014		14,985,704	72,727
Proceeds from follow-on offering, net of costs	61,397	$ 30		61,367
Proceeds from follow-on offering, net of costs (in shares)		3,000,000
Employee stock-based compensation expense	2,382			2,382
Stock option exercises	119			119
Stock option exercises (in shares)		36,189
Employee stock purchase program (ESPP)	564			564
Employee stock purchase program (ESPP) (in shares)		44,250
Net loss	(41,230)				(41,230)
Balance, end of year at Dec. 31, 2015	118,871	$ 180	$ (260)	294,227	(175,276)
Balance, end of year (in shares) at Dec. 31, 2015		18,066,143	72,727
Employee stock-based compensation expense	3,236			3,236
Stock option exercises	923	$ 5		918
Stock option exercises (in shares)		478,099
Employee stock purchase program (ESPP)	753	$ 1		752
Employee stock purchase program (ESPP) (in shares)		122,667
Vested restricted stock (in shares)		4,500
Net loss	(40,166)				(40,166)
Balance, end of year at Dec. 31, 2016	83,617	$ 186	$ (260)	299,133	(215,442)
Balance, end of year (in shares) at Dec. 31, 2016		18,671,409	72,727
Employee stock-based compensation expense	6,766			6,766
Stock option exercises	1,346	$ 5		1,341
Stock option exercises (in shares)		480,236
Employee stock purchase program (ESPP)	647	$ 1		646
Employee stock purchase program (ESPP) (in shares)		108,081
Vested restricted stock		$ 3		(3)
Vested restricted stock (in shares)		293,910
Shares withheld for tax obligations on vested RSUs	(725)	$ (1)		(724)
Shares withheld for tax obligations on vested RSUs, shares		(78,934)
Net loss	(64,028)				(64,028)
Balance, end of year at Dec. 31, 2017	$ 27,623	$ 194	$ (260)	$ 307,159	$ (279,470)
Balance, end of year (in shares) at Dec. 31, 2017		19,474,702	72,727

Consolidated Statements of Cash

Consolidated Statements of Cash Flows - USD ($)	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Cash flows from operating activities:
Net loss	$ (64,028,000)	$ (40,166,000)	$ (41,230,000)
Adjustments to reconcile net loss to net cash used in operating activities:
Goodwill impairment			14,278,000
Depreciation and amortization	3,034,000	1,177,000	318,000
Provision for doubtful accounts	493,000	437,000	233,000
Provision for warranties	294,000	71,000	385,000
Provision for inventory	3,125,000	1,323,000	469,000
Amortization of acquired inventory step-up	999,000	61,000
Change in fair value of warrants	95,000	39,000	(360,000)
Change in fair value of deferred and contingent consideration	1,025,000	37,000
Non-cash portion of debt extinguishment loss	17,000
Amortization of debt discount and issuance costs	140,000
Non-cash interest expense	1,000	3,000	1,386,000
Stock-based compensation expense	6,766,000	3,236,000	2,382,000
Loss on disposal of property and equipment	25,000	124,000
Deferred income taxes	(21,000)	61,000	0
Changes in assets and liabilities, net of effects from acquisitions:
Accounts receivable	(1,890,000)	927,000	715,000
Inventories	527,000	2,390,000	(898,000)
Prepaid expenses, other current assets and other assets	674,000	(529,000)	147,000
Insurance recovery receivable	9,336,000	(9,375,000)
Accounts payable	1,290,000	(564,000)	1,546,000
Accrued and other liabilities	3,218,000	(1,422,000)	1,571,000
Legal settlement payable	(9,900,000)	10,900,000
Customer deposits	(1,136,000)	(3,160,000)	874,000
Net cash used in operating activities	(45,916,000)	(34,430,000)	(18,184,000)
Cash flows from investing activities:
Purchase of property and equipment	(1,864,000)	(1,126,000)	(1,128,000)
Business acquisitions, net of cash acquired	(18,455,000)	(11,709,000)
Net cash used in investing activities	(20,319,000)	(12,835,000)	(1,128,000)
Cash flows from financing activities:
Proceeds from exercise of stock options	1,346,000	923,000	119,000
Proceeds from issuance of common stock under ESPP	647,000	753,000	564,000
Tax payments related to shares withheld for vested restricted stock units (RSUs)	(725,000)
Proceeds from issuance of common stock, net of underwriters discount			62,040,000
Deferred equity issuance costs, IPO			(71,000)
Deferred equity issuance costs, follow-on offering			(643,000)
Repayment of long-term debt			(26,625,000)
Gross borrowings under the Term Loan	25,000,000
Gross borrowings under the Revolving Line of Credit	5,000,000
Repayment of the Revolving Line of Credit	(5,000,000)
Deferred financing costs	(657,000)
Net cash provided by financing activities	25,611,000	1,676,000	35,384,000
Net decrease in cash and cash equivalents	(40,624,000)	(45,589,000)	16,072,000
Cash and cash equivalents at:
Beginning of period	67,212,000	112,801,000	96,729,000
End of period	26,588,000	67,212,000	112,801,000
Supplemental disclosure of cash flow information:
Interest paid	870,000	96,000	1,884,000
Supplemental disclosure of non-cash investing and financing activities:
Property and equipment in accounts payable and accrued liabilities	1,088,000	939,000	$ 22,000
Acquisition of business, deferred and contingent consideration obligations at fair value	10,912,000	$ 1,600,000
Forgiveness of SVB Loan commitment fee	750,000
Accrued deferred financing costs	$ 6,000

Formation and Business of the C

Formation and Business of the Company	12 Months Ended
	Dec. 31, 2017
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) Follow-on Offering On September 23, 2015, the Company closed a follow-on public offering, whereby it sold 3,000,000 shares of its common stock, at a price to the public of $22.00 per share. The Company received net proceeds from the follow-on offering of approximately $61.4 million, after deducting underwriting discounts and commissions of $4.0 million and offering expenses of approximately $0.6 million. (c) 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. (d) 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 PMA supplement to the FDA for the manufacturing of the Company’s PMA-approved breast implants by Vesta. 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 their 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 supplements. In addition to approving the manufacturing site-change supplement, the FDA has approved two (2) of these three (3) process enhancement supplements, while requesting additional information for the third submission. The Company continues to work closely with the FDA to address their information requests related to this third and final outstanding submission in order to resolve these matters in a timely manner (e) Regulatory Inquiries Regarding Products Manufactured by Silimed There have been regulatory inquiries related to medical devices manufactured by Silimed Indústria de Implantes Ltda. (formerly, Silimed-Silicone e Instrumental Medico-Cirugio e Hospitalar Ltda.), or Silimed, the Company’s former sole source contract manufacturer for its silicone gel breast implants. Following extensive independent, third-party testing and analyses of its devices manufactured by Silimed, which tests indicated no significant safety concerns with the use of Silimed’s products, the Company lifted the temporary hold on the sale of such devices. While the Company continues to sell its remaining inventory of devices manufactured by Silimed, its existing manufacturing contract with Silimed expired on its terms in April 2017 and the Company did not renew the contract.

Summary of Significant Accounti

Summary of Significant Accounting Policies	12 Months Ended
	Dec. 31, 2017
Accounting Policies [Abstract]
Summary of Significant Accounting Policies	(2) Summary of Significant Accounting Policies (a) Basis of Presentation and Use of Estimates The preparation of financial statements in conformity with accounting principles generally accepted in the United States of America, or GAAP, requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities and the disclosure of contingent assets and liabilities at the dates of the financial statements, and the reported amounts of revenues and expenses during the reporting period. Actual results could differ from those estimates. Assets and liabilities which are subject to significant judgment and use of estimates include the allowance for doubtful accounts, sales return reserves, provision for warranties, valuation of inventories, recoverability of long-lived assets, valuation allowances with respect to deferred tax assets, useful lives associated with property and equipment and finite lived intangible assets, and the valuation and assumptions underlying stock-based compensation and other equity instruments. On an ongoing basis, the Company evaluates its estimates compared to historical experience and trends, which form the basis for making judgments about the carrying value of assets and liabilities. In addition, the Company engages the assistance of valuation specialists in concluding on fair value measurements in connection with stock-based compensation and other equity instruments. (b) Going Concern Since inception, the Company has incurred net losses. During the years ended December 31, 2017, 2016 and 2015 the Company incurred net losses of $64.0 million, $40.2 million and $41.2 million, respectively. The Company used $45.9 million of cash in operations for the year ended December 31, 2017, $34.4 million for the year ended December 31, 2016 and $18.2 million for the year ended December 31, 2015. At December 31, 2017 and 2016 the Company had an accumulated deficit of $279.5 million and $215.4 million, respectively. At December 31, 2017, the Company had cash and cash equivalents of $26.6 million. These consolidated financial statements have been prepared assuming that the Company will continue as a going concern and do not include any adjustments that might result from the outcome of this uncertainty. The Company has incurred recurring losses from operations and cash outflows from operating activities that raise substantial doubt about its ability to continue as a going concern. In addition, while the Company was in compliance with the financial covenants in its credit agreement with MidCap Financial Trust at December 31, 2017, given the potential violations of those covenants during fiscal year 2018, the Company has classified the debt as current in the consolidated balance sheet at December 31, 2017. Management has taken and is taking actions to improve our liquidity. For example, the Company has the ability to receive a $10.0 million term loan pursuant to our credit agreement with MidCap Financial Trust, upon receipt of FDA certifications of the manufacturing facility operated by Vesta by March 31, 2018. In addition, in February 2018, the Company entered into an At-The-Market Equity Offering Sales Agreement with Stifel, Nicolaus & Company, Incorporated 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 million. In addition, the Company may raise additional capital through the sale of equity securities and incremental debt financing. While there can be no assurances that the Company will be successful in obtaining the level of financing needed for its operations, the Company believes it is probable that the actions taken, together with any additional equity or debt financing the Company may pursue, will be sufficient to address liquidity needs and alleviate the substantial doubt about the Company’s ability to continue as a going concern for a reasonable period of time. If the Company is unsuccessful in raising capital, it may need to reduce activities, curtail or cease certain operations. (c) Cash and Cash Equivalents The Company considers all highly liquid investments purchased with an original maturity of three months or less when purchased to be cash equivalents. Cash and cash equivalents consist primarily of cash in checking accounts and interest-bearing money market accounts. (d) Concentration of Credit and Supplier Risks Financial instruments that potentially subject the Company to significant concentrations of credit risk consist primarily of cash and cash equivalents. The Company’s cash and cash equivalents are deposited in demand accounts at a financial institution that management believes is creditworthy. The Company is exposed to credit risk in the event of default by this financial institution for cash and cash equivalents in excess of amounts insured by the Federal Deposit Insurance Corporation, or FDIC. Management believes that the Company’s investments in cash and cash equivalents are financially sound and have minimal credit risk and the Company has not experienced any losses on its deposits of cash and cash equivalents. The Company relies on a limited number of third-party manufacturers for the manufacturing and supply of its products. This could result in the Company not being able to acquire the inventory needed to meet customer demand, which would result in possible loss of sales and affect operating results adversely. (e) Fair Value of Financial Instruments The carrying amounts of cash and cash equivalents, accounts receivable, accounts payable, accrued liabilities, and customer deposits are reasonable estimates of their fair value because of the short maturity of these items. The fair value of the common stock warrant liability, deferred and contingent consideration are discussed in Note 2. The fair value of the debt is based on the amount of future cash flows associated with the instrument discounted using the Company’s market rate. As of December 31, 2017, the carrying value of the debt is presented as a current liability of $24.6 million, representing the principal obligations, net of debt issuance costs, owed under the term loan. (f) 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 deferred consideration and 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 from SSP and the deferred and 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 deferred consideration and 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 December 31, 2017 and 2016 and indicate the level of the fair value hierarchy utilized to determine such fair value (in thousands): 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 deferred consideration — — 1,255 1,255 Liability for contingent consideration — — 12,319 12,319 $ — — 13,768 13,768 Fair Value Measurements as of December 31, 2016 Using: Level 1 Level 2 Level 3 Total Liabilities: Liability for common stock warrants $ — — 99 99 Liability for deferred consideration — — 395 395 Liability for contingent consideration — — 1,242 1,242 $ — — 1,736 1,736 The liability for common stock warrants and the current portion of deferred consideration is included in “accrued and other current liabilities” and the long-term liabilities for the deferred consideration and contingent consideration are included in “deferred and contingent consideration” in the consolidated balance sheet. The following table provides a rollforward of the aggregate fair values of the Company’s common stock warrants, deferred and contingent consideration for which fair value is determined by Level 3 inputs (in thousands): Warrant Liability Balance, December 31, 2016 $ 99 Fair value of warrants to be issued upon borrowing under the SVB Loan Agreement (Note 5) 88 Warrants extinguished upon termination of SVB Loan Agreement (88 ) Change in fair value through December 31, 2017 95 Balance, December 31, 2017 $ 194 Deferred Consideration Liability Balance, December 31, 2016 $ 395 Initial fair value of acquisition-related deferred consideration 966 Change in fair value of deferred consideration (106 ) Balance, December 31, 2017 $ 1,255 Contingent Consideration Liability Balance, December 31, 2016 $ 1,242 Initial fair value of acquisition-related contingent consideration 9,946 Change in fair value of contingent consideration 1,131 Balance, December 31, 2017 $ 12,319 In connection with the acquisition of miraDry on July 25, 2017, contingent consideration of up to an aggregate of $14.0 million may be payable upon achieving certain future sales milestones and had a fair value of $10.4 million at December 31, 2017. In connection with the acquisition of the tissue expander portfolio from SSP on November 2, 2016, contingent consideration of up to an aggregate of $2.0 million may be payable upon achieving certain future sales milestones and had a fair value of $1.8 million and $1.1 million at December 31, 2017 and 2016, respectively. The Company recognizes changes in the fair value of the warrants in “other income (expense), net” in the consolidated statement of operations and changes in deferred consideration and contingent consideration are recognized in “general and administrative” expense in the consolidated statement of operations. (g) Property and Equipment Property and equipment are stated at cost, net of accumulated depreciation. Depreciation is computed using the straight‑line method over the estimated useful life of the asset, generally three to five years. Leasehold improvements are depreciated over the shorter of the lease term or the estimated useful life of the related asset. Upon retirement or sale of an asset, the cost and related accumulated depreciation or amortization are removed from the consolidated balance sheet and any resulting gain or loss is reflected in operations in the period realized. Maintenance and repairs are charged to operations as incurred. (h) Goodwill and Other Intangible Assets Goodwill represents the excess of the purchase price over the fair value of net assets of purchased businesses. Goodwill is not amortized, but instead is subject to impairment tests on at least an annual basis and whenever circumstances suggest that goodwill may be impaired. After the acquisition of miraDry, management began evaluating the Company as two reporting units, Breast Products and miraDry. 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 more likely than not that the fair value of a reporting unit is less than its carrying amount, the Company will recognize an impairment charge for the amount by which the carrying amount exceeds the reporting unit’s fair value. The Company tests indefinite-lived intangible assets for impairment on at least an annual basis and whenever circumstances suggest the assets may be impaired. The Company’s annual test for impairment is performed as of October 1 of each fiscal year. If indicators of impairment are present, the Company evaluates the carrying value of the intangible assets in relation to estimates of future undiscounted cash flows. If the carrying value of the intangible asset exceeds its fair value, an impairment loss is recognized in an amount equal to the difference. Judgments about the recoverability of purchased finite‑lived intangible assets are made whenever events or changes in circumstance indicate that impairment may exist. Each fiscal year the Company evaluates the estimated remaining useful lives of purchased intangible assets and whether events or changes in circumstance warrant a revision to the remaining periods of amortization. Recoverability of finite‑lived intangible assets is measured by comparison of the carrying amount of the asset to the future undiscounted cash flows the asset is expected to generate. The intangible asset is amortized to the consolidated statement of operations based on estimated cash flows generated from the intangible over its estimated life. ( i ) Impairment of Long‑Lived Assets The Company’s management routinely considers whether indicators of impairment of long‑lived assets are present. If such indicators are present, management determines whether the sum of the estimated undiscounted cash flows attributable to the assets in question is less than their carrying value. If less, the Company will recognize an impairment loss based on the excess of the carrying amount of the assets over their respective fair values. Fair value is determined by discounted future cash flows, appraisals or other methods. If the assets determined to be impaired are to be held and used, the Company will recognize an impairment charge to the extent the present value of anticipated net cash flows attributable to the asset are less than the asset’s carrying value. The fair value of the asset will then become the asset’s new carrying value. There have been no impairments of long‑lived assets recorded during the years ended December 31, 2017, 2016 and 2015. The Company may record impairment losses in future periods if factors influencing its estimates change. (j) Business Combinations Business combinations are accounted for using the acquisition method of accounting. Under the acquisition method, assets acquired and liabilities assumed are recorded at their respective fair values as of the acquisition date in our financial statements. The excess of the fair value of consideration transferred over the fair value of the net assets acquired is recorded as goodwill. Contingent consideration obligations incurred in connection with a business combination are recorded at their fair values on the acquisition date and remeasured at their fair values each subsequent reporting period until the related contingencies are resolved. The resulting changes in fair values are recorded in earnings. (k) Reportable 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. Based on the financial information presented to and reviewed by the CODM, the Company has determined that it has two reportable segments: Breast Products and miraDry. (l) Revenue Recognition The Company recognizes revenue related to sales of products directly to customers in markets where it has regulatory approval, net of trade discounts and allowances, provided that (i) persuasive evidence of an arrangement exists, (ii) delivery has occurred and title and risk of loss have transferred, (iii) the price is fixed or determinable and (iv) collectability is reasonably assured. Sales prices are documented in the executed sales contract or purchase order prior to shipment. The Company evaluates the creditworthiness of customers to determine that appropriate credit limits are established prior to the acceptance of an order. Revenue for extended warranties and service agreements are recognized ratably over the term of the agreement. 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 warehouse. The Company also leverages a distributor network for selling the miraDry System internationally. The Company recognizes revenue when title to the product and risk of loss transfer to customers, provided there are no remaining performance obligations required of the Company or any written matters requiring customer acceptance, which generally occurs upon shipment. Standard terms in these agreements do not allow for trial periods, rights of return, refunds, payments contingent on obtaining financing or other terms that could impact the customer’s obligation. Appropriate reserves are established for anticipated sales returns based on historical experience, recent gross sales and any notification of pending returns. For Breast Products specifically, the Company allows for the return of Breast Products from customers within six months after the original sale and records estimated sales returns as a reduction of sales in the same period revenue is recognized. Sales return provisions are calculated based upon historical experience with actual returns. 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 $3.9 million as of both December 31, 2017 and 2016, recorded net against accounts receivable in the consolidated balance sheet. Shipping and handling charges are largely provided to customers free of charge for breast products. The associated costs are viewed as part of the Company’s marketing programs and are recorded as a component of sales and marketing expense in the consolidated statement of operations as an accounting policy election. Shipping and handling charges are typically billed to the customer for sales of the miraDry Systems and are recorded as a component of cost of goods sold in the consolidated statement of operations. For the years ended 2017, 2016 and 2015 shipping costs amounted to $1.0 million, $0.6 million and $1.1 million, respectively. (m) Accounts Receivable and Allowance for Doubtful Accounts Accounts receivable are recorded at the invoiced amount and do not bear interest. The Company maintains allowances for doubtful accounts for estimated losses resulting from the inability to collect from some of its customers. The allowances for doubtful accounts are based on the analysis of historical bad debts, customer credit‑worthiness, past transaction history with the customer, and current economic trends. If the financial condition of the Company’s customers were to deteriorate, adversely affecting their ability to make payments, additional allowances may be required. The Company has established an allowance for doubtful accounts of $0.9 million and $0.4 million as of December 31, 2017 and 2016, respectively. (n) Inventories and Cost of Goods Sold Inventories represent raw materials, work in process and finished goods that are recorded at the lower of cost or market on a first‑in, first‑out basis, or FIFO. miraDry inventory costs are determined using a standard cost, which approximates actual cost on an average cost basis. The Company periodically assesses the recoverability of all inventories to determine whether adjustments for impairment or obsolescence are required. The Company evaluates the remaining shelf life and other general obsolescence and impairment criteria in assessing the recoverability of the Company’s inventory. The Company recognizes the cost of inventory transferred to the customer in cost of goods sold when revenue is recognized. At December 31, 2017 and 2016, approximately $1.6 million and $2.0 million, respectively, of the Company’s Breast Products segment inventory was held on consignment at doctors’ offices, clinics, and hospitals. The value and quantity at any one location is not significant. (o) Income Taxes The Company accounts for income taxes under the asset and liability method. Under this method, deferred tax assets and liabilities are determined based on the difference between the financial statement and tax bases of assets and liabilities using enacted tax rates in effect for the year in which the differences are expected to affect taxable income. Valuation allowances are established when necessary to reduce deferred tax assets to the amounts expected to be realized. The Company the Company The Company accounts for uncertain tax position in accordance with ASC 740‑10, Accounting for Uncertainty in Income Taxes (p) Research and Development Expenditures Research and development costs are charged to operating expenses as incurred. Research and development, or R&D, primarily consist of clinical expenses, regulatory expenses, product development, consulting services, outside research activities, quality control and other costs associated with the development of the Company’s products and compliance with Good Clinical Practices, or GCP, requirements. R&D expenses also include related personnel and consultant compensation and stock-based compensation expense. (q) Advertising Expenses related to advertising are charged to sales and marketing expense as incurred. Advertising costs were $1.8 million, $0.6 million and $1.0 million for the years ended December 31, 2017, 2016 and 2015, respectively. (r) Stock‑Based Compensation The Company applies the fair value provisions of ASC 718, Compensation — Stock Compensation The option-pricing models require the input of subjective assumptions, including the risk‑free interest rate, expected dividend yield, expected volatility and expected term, among other inputs. These estimates involve inherent uncertainties and the application of management’s judgment. If factors change and different assumptions are used, our stock‑based compensation expense could be materially different in the future. These assumptions are estimated as follows: • Risk‑free interest rate —The risk‑free interest rate is based on the yields of U.S. Treasury securities with maturities similar to the expected term of the options for each option group. • Dividend yield —We have never declared or paid any cash dividends and do not presently plan to pay cash dividends in the foreseeable future. Consequently, we used an expected dividend yield of zero. • Expected volatility —As we do not have a significant trading history for our common stock, the expected stock price volatility for our common stock was estimated by taking the average of (i) the median historic price volatility and (ii) the median of the implied volatility averages, with a three‑month lookback from the valuation date, for any trading options of industry peers based on daily price observations over a period equivalent to the expected term of the time to a liquidity event. We intend to continue to consistently apply this process using the same or similar public companies until a sufficient amount of historical information regarding the volatility of our own common stock share price becomes available. • Expected term —The expected term represents the period that our stock‑based awards are expected to be outstanding. During the year ended December 31, 2017, the Company adopted ASU 2016-09, Compensation—Stock Compensation (Topic 718): Improvements to Employee Share-Based Payment Accounting The following table presents the weighted‑average assumptions used to estimate the fair value of options granted during the periods presented: Year Ended December 31, Stock Options 2017 2016 2015 Expected term (in years) 4.47 to 6.07 5.47 to 6.07 5.27 to 6.08 Expected volatility 45 % to 56 % 51 % to 53 % 45 % to 52 % Risk-free interest rate 1.24 % to 2.45 % 1.42 % to 1.54 % 1.48 % to 1.92 % Dividend yield — — — The following table presents the weighted-average assumptions used to estimate the fair value of the stock purchase rights granted under the employee stock purchase plan: Year Ended December 31, ESPP 2017 2016 2015 Expected term (in years) 0.50 to 2.10 0.50 to 2.10 0.50 to 2.10 Expected volatility 46 % to 55 % 42 % to 58 % 42 % to 44 % Risk-free interest rate 0.08 % to 1.30 % 0.08 % to 0.85 % 0.08 % to 0.71 % Dividend yield — — — (s) Product Warranties The Company offers a limited warranty and a lifetime product replacement program for the Company’s silicone gel breast implants and a product warranty for the Company’s miraDry Systems. Under the breast implant limited warranty, the Company will reimburse patients for certain out-of-pocket costs related to revision surgeries performed within ten years from the date of implantation in a covered event. Under the breast implant lifetime product replacement program, the Company provides no-charge replacement breast implants if a patient experiences a covered event. Under the miraDry warranty, the Company currently provides a standard product warranty for the consoles, handpieces and the miraDry consumables, or bioTips. Additionally, an extended miraDry warranty may be purchased to provide additional protection of the miraDry System. The portion of the warranty provision expected to be incurred within 12 months is classified as current within accrued liabilities and other, while the remaining amount is classified as long-term within warranty reserve and other long-term liabilities The following table provides a rollforward of the accrued warranties (in thousands): Year Ended December 31, 2017 2016 Beginning balance as of January 1 $ 1,378 $ 1,332 Assumed warranty liability from acquisition 137 — Warranty costs incurred during the period (167 ) (25 ) Changes in accrual related to warranties issued during the period 301 177 Changes in accrual related to pre-existing warranties (7 ) (106 ) Balance as of December 31 $ 1,642 $ 1,378 (t) Net Loss Per Share December 31, 2017 2016 2015 Net loss (in thousands) $ (64,028 ) $ (40,166 ) $ (41,230 ) Weighted average common shares outstanding, basic and diluted 19,159,057 18,233,177 15,770,972 Net loss per share attributable to common stockholders $ (3.34 ) $ (2.20 ) $ (2.61 ) The Company excluded the following potentially dilutive securities, outstanding as of December 31, 2017, 2016 and 2015 from the computation of diluted net loss per share attributable to common stockholders for the years ended December 31, 2017, 2016 and 2015 because they had an anti-dilutive impact due to the net loss attributable to common stockholders incurred for the periods. December 31, 2017 2016 2015 Stock options to purchase common stock 1,867,627 2,057,296 1,967,906 Warrants for the purchase of common stock 47,710 47,710 47,710 1,915,337 2,105,006 2,015,616 (u) Recent Accounting Pronouncements Recently Adopted Accounting Standards In July 2015, the FASB issued ASU 2015-11, Inventory - Simplifying the Measurement of Inventory In March 2016, the FASB issued ASU 2016-09, Compensation - Stock Compensation (Topic 718). In January 2017, the FASB issued ASU 2017-04, Intangibles - Goodwill and Other (Topic 350) - Simplifying the Test for Goodwill Impairment eliminates Step 2 from the goodwill impairment test. The Recently Issued Accounting Standards In May 2014, the FASB issued ASU 2014-09, Revenue from Contracts with Customers Revenue from Contracts with Customers (Topic 606): Deferral of the Effective Date, In December 2016, the FASB issued ASU 2016-20, Technical Corrections and Improvements to Topic 606, Revenue from Contracts with Customers. ASU 2016-20 is intended to clarify and suggest improvements to the application of current standards under Topic 606 and other Topics amended by ASU 2014-09, Revenue from Contracts with Customers (Topic 606) . The effective date of ASU 2016-20 is the same as the effective date for ASU 2014-09. In February 2016, the FASB issued ASU 2016-02, Leases (Topic 842) Leases (Topic 840). In January 2017, the FASB issued ASU 2017-01, Business Combinations (Topic 805) - Clarifying the Definition of a Business . The standard The updated accounting standard will be effective for the Company beginning in fiscal year 2018. . 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 (v) Reclassifications Certain reclassifications have been made to prior year amounts to conform to the current year presentation.

Acquisitions

Acquisitions	12 Months Ended
	Dec. 31, 2017
Business Combinations [Abstract]
Acquisitions	(1) 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 million. The transaction, which closed on July 25, 2017, or the Acquisition Date, added the miraDry System, the only FDA cleared device to reduce underarm sweat, odor and permanently reduce hair of all colors, to Sientra’s aesthetics portfolio. In connection with the acquisition, the Company recorded $3.1 million of professional fees for the year ended December 31, 2017, which are included in general and administrative expense. The aggregate preliminary 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 relates 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. 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 2. The contingent consideration component is subject to the recognition of subsequent changes in fair value through general and administrative expense in the 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 preliminary 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 expected to be deductible for tax purposes. A summary of the intangible assets acquired, estimated useful lives and amortization method 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; however, the purchase price allocation has not been finalized. This could result in adjustments to the carrying value of the assets acquired and liabilities assumed, the useful lives of intangible assets and residual amount allocated to goodwill. The preliminary allocation of the purchase price is based on the best estimates of management and is subject to revision based on the final valuations and estimates of useful lives. 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 2016. 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 consolidated results of operations of the combined business had the merger actually occurred at the beginning of fiscal year 2016 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): December 31, 2017 2016 Pro Forma Net sales $ 46,747 $ 41,179 Net loss (69,545 ) (69,226 ) Pro forma loss per share attributable to ordinary shares - basic and diluted $ (3.62 ) $ (3.78 ) (b) Acquisition of BIOCORNEUM On March 9, 2016, the Company entered into an asset purchase agreement with Enaltus LLC, or Enaltus, to acquire exclusive U.S. rights to BIOCORNEUM, an advanced silicone scar treatment marketed exclusively to physicians. The acquisition of BIOCORNEUM aligns with the Company’s business development objectives and adds a complementary product that serves the needs of its customers. In connection with the acquisition, the Company recorded $0.2 million of professional fees for the year ended, December 31, 2016 which is included in general and administrative expense. The aggregate acquisition date fair value of the consideration transferred was approximately $7.4 million, which consisted of the following (in thousands): Fair Value Cash $ 6,859 Deferred consideration 434 Contingent consideration 116 $ 7,409 The deferred consideration and contingent consideration consist of future royalty payments to be paid on a quarterly basis to Enaltus on future BIOCORNEUM sales for the 4.5 years beginning January 1, 2024. The Company determined the fair value of the deferred consideration and contingent consideration at the acquisition date using a Monte-Carlo simulation model. The fair value of the deferred consideration is based on the future minimum royalty payments using the risk-free U.S. Treasury yield curve discount rate. The minimum estimated future payments due under the deferred consideration are $0.5 million. The fair value of the contingent consideration is based on projected future BIOCORNEUM sales and a risk-adjusted discount rate. The terms of the agreement do not provide for a limitation on the maximum potential future payments. The inputs are significant inputs not observable in the market, which are referred to as Level 3 inputs and are further discussed in Note 2. The deferred consideration and contingent consideration components are subject to the recognition of subsequent changes in fair value through general and administrative expense in the consolidated statement of operations. The Company allocated the total consideration transferred to the tangible and identifiable intangible assets acquired based on their respective fair values on the acquisition date, with the remaining unallocated amount recorded as goodwill. The goodwill arising from the transaction is primarily attributable to expected operational synergies, and all of goodwill will be deductible for income tax purposes. The consolidated financial statements for the years ended December 31, 2017 and 2016 include the results of operations of BIOCORNEUM from the date of acquisition. The following table summarizes the allocation of the fair value of the consideration transferred by major class for the business combination completed on March 9, 2016 (in thousands): March 9, 2016 Inventories, net $ 100 Prepaid expenses 36 Goodwill 3,273 Intangible assets 4,000 $ 7,409 A summary of the intangible assets acquired, estimated useful lives and amortization method is as follows (in thousands): Estimated useful Amortization Amount life (in years) method Customer relationships $ 3,200 10 Accelerated Trade name 800 12 Straight-line $ 4,000 The Company retained an independent third-party appraiser to assist management in its valuation and the purchase price has been finalized. Pro forma results of operations have not been presented because the effect of the acquisition was not material to the Company's results of operations. (c) Acquisition of Tissue Expander Portfolio from Specialty Surgical Products, Inc. On November 2, 2016, the Company entered into an asset purchase agreement with Specialty Surgical Products, Inc., or SSP, to acquire c ertain assets, consisting of the Dermaspan, Softspan, and AlloX2 tissue expanders, from SSP. Fair Value Cash $ 4,950 Contingent consideration 1,050 $ 6,000 The contingent consideration consists of future cash payments of a maximum of $2.0 million to be paid to SSP based upon the achievement of certain milestones of future net sales. The Company determined the fair value of the contingent consideration at the acquisition date 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 2. The contingent consideration components are subject to the recognition of subsequent changes in fair value through general and administrative expense in the consolidated statement of operations. The Company allocated the total consideration transferred to the tangible and identifiable intangible assets acquired and liabilities assumed based on their respective fair values on the acquisition date, with the remaining unallocated amount recorded as goodwill. The goodwill arising from the transaction is primarily attributable to expected operational synergies, and all of goodwill will be deductible for income tax purposes. The financial statements for the years ended December 31, 2016 and 2017 include the results of operations of the Dermaspan, Softspan, and AlloX2 tissue expanders The following table summarizes the allocation of the fair value of the consideration transferred by major class for the business combination completed on November 2, 2016 (in thousands): November 2, 2016 Accounts receivable, net $ 196 Inventories, net 1,555 Equipment 34 Goodwill 1,605 Intangible assets 2,860 Liabilities assumed (250 ) $ 6,000 A summary of the intangible assets acquired, estimated useful lives and amortization method is as follows (in thousands): Estimated useful Amortization Amount life method Customer relationships $ 1,740 9 years Accelerated Regulatory approvals 670 14 months Straight-line Trade names 450 indefinite-lived $ 2,860 The Company retained an independent third-party appraiser to assist management in its valuation and the purchase price has been finalized. Pro forma results of operations have not been presented because the effect of the acquisition was not material to the Company's results of operations.

Balance Sheet Components

Balance Sheet Components	12 Months Ended
	Dec. 31, 2017
Balance Sheet Related Disclosures [Abstract]
Balance Sheet Components	(4) Balance Sheet Components Inventories, net consist of the following (in thousands): December 31, 2017 2016 Raw materials $ 1,642 $ — Work in progress 3,956 — Finished goods 15,298 18,484 $ 20,896 $ 18,484 Property and equipment, net consist of the following (in thousands): December 31, 2017 2016 Leasehold improvements $ 402 $ 86 Manufacturing equipment and toolings 4,260 2,264 Computer equipment 387 287 Software 797 669 Office equipment 142 129 Furniture and fixtures 816 743 6,804 4,178 Less accumulated depreciation (2,041 ) (1,192 ) $ 4,763 $ 2,986 Depreciation expense for the years ended December 31, 2017, 2016 and 2015 was $0.9 million, $0.4 million and $0.3 million, respectively. Accrued and other current liabilities consist of the following: December 31, 2017 2016 Payroll and related expenses $ 3,579 $ 2,592 Accrued commissions 3,297 1,222 Accrued equipment 1,091 887 Deferred consideration, current portion 977 — Audit, consulting and legal fees 920 803 Accrued sales and marketing expenses 794 39 Other 2,816 964 $ 13,474 $ 6,507

Debt and Revolving Loan

Debt and Revolving Loan	12 Months Ended
	Dec. 31, 2017
Debt Disclosure [Abstract]
Debt and Revolving Loan	(5) 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. Upon executing the Credit Agreements, the Company repaid in full its indebtedness under the SVB Loan Agreement, which totaled approximately $5.0 million related to a revolving line of credit, or the Revolving Line of Credit. In connection with the refinancing, the Company was forgiven a commitment fee payable of approximately $0.8 million, which was included in long term liabilities, net of the current portion included in accrued and other current liabilities in the consolidated balance sheet, and corresponding warrants of approximately $0.1 million related to the SVB Loan Agreement were extinguished. The Company also recorded an expense of approximately $16 thousand related to the write-off of related issuance costs, which has been included in interest expense in the consolidated statements of operations. Unamortized debt issuance costs from the SVB Loan Agreement related to the modification will be amortized over the term of the new Credit Agreements. Under the terms of the Term Loan Credit Agreement, as of July 25, 2017, Midcap funded $ 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 December 31, 2017 was 1.36%, 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. 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 December 31, 2017, there was $25.0 million outstanding related to the Term Loans. As of December 31, 2017, the unamortized debt issuance costs on the Term Loans was approximately $0.3 million and are included as a reduction to the current portion of long-term debt on the 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 may prepay all of the outstanding balance prior to the maturity date provided the Company pays Midcap a prepayment fee. The Company paid an origination fee of 0.50% of the Revolving Loan amount of $10.0 million on the closing date. As of December 31, 2017, there were no borrowings outstanding related to the Revolving Loan. As of December 31, 2017, the unamortized debt issuance costs related to the Revolving Loan was approximately $0.1 million and was included in prepaid expenses and other current assets on the consolidated balance sheet. The amortization of debt issuance costs for the year ended December 31, 2017 was $0.1 million, relating to the Revolving Line of Credit, the Term Loans, and the Revolving Loan and were included in interest expense in the consolidated statement of operations. The Credit Agreements includes 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, other than intellectual property. While the Company was in compliance with the financial covenants in its credit agreement with MidCap at December 31, 2017, given the potential violations of those covenants during fiscal year 2018, as discussed in Note 2, the Company has classified the debt, net of unamortized debt issuance costs, as current in the consolidated balance sheet at December 31, 2017. On this basis, as of December 31, 2017, the future debt payments of $25.0 million are considered payable in 2018.

Goodwill and Other Intangible A

Goodwill and Other Intangible Assets, net	12 Months Ended
	Dec. 31, 2017
Goodwill And Intangible Assets Disclosure [Abstract]
Goodwill and Other Intangible Assets, net	(6) Goodwill and Other Intangible Assets, net (a) Goodwill The Company has determined that it has two reporting units, Breast Products and miraDry, and evaluates goodwill for impairment at least annually on October 1 st The changes in the carrying amount of goodwill during the years ended December 31, 2017 and 2016 were as follows (in thousands): Balances as of December 31, 2015 Breast Product miraDry Total Goodwill $ 14,278 $ — $ 14,278 Accumulated impairment losses (14,278 ) — (14,278 ) Goodwill, net $ — $ — $ — Goodwill acquired 4,878 — 4,878 Balances as of December 31, 2016 Goodwill $ 19,156 $ — $ 19,156 Accumulated impairment losses (14,278 ) — (14,278 ) Goodwill, net $ 4,878 $ — $ 4,878 Goodwill acquired (Note 3) — 7,629 7,629 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 During 2015, the Company experienced a significant sustained decline in stock price, the impact of regulatory inquiries and the fire at Silimed’s facility for manufacturing Sientra’s breast implants. These factors were identified as indicators of impairment. As a result of the analysis performed, the Company recorded a goodwill impairment charge of $14.3 million for the year ended December 31, 2015. The Company conducted the annual goodwill impairment test in the fourth quarter of 2016 and 2017 and determined goodwill had not been impaired for the years ended December 31, 2017 and 2016. (b) Other Intangible Assets The components of the Company’s other intangible assets consist of the following definite-lived and indefinite-lived assets (in thousands): 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 December 31, 2016 Average Amortization Period Gross Carrying Accumulated Intangible (in years) Amount Amortization Assets, net Intangibles with definite lives Customer relationships 10 $ 4,940 $ (602 ) $ 4,338 Trade names - finite life 12 800 (56 ) 744 Regulatory approvals 1 670 (96 ) 574 Non-compete agreement 2 80 (17 ) 63 Acquired FDA non-gel product approval 11 1,713 (1,696 ) 17 Total definite-lived intangible assets $ 8,203 $ (2,467 ) $ 5,736 Intangibles with indefinite lives Trade names - indefinite life — 450 — 450 Total indefinite-lived intangible assets $ 450 $ — $ 450 Amortization expense for the year ended December 31, 2017, 2016 and 2015 was $2.2 million, $0.8 million and $0.1 million, respectively. The following table summarizes the estimated amortization expense relating to the Company's intangible assets as of December 31, 2017 (in thousands): Amortization Period Expense 2018 $ 2,308 2019 2,321 2020 2,209 2021 1,996 2022 1,762 Thereafter 7,757 $ 18,353

Income Taxes

Income Taxes	12 Months Ended
	Dec. 31, 2017
Income Tax Disclosure [Abstract]
Income Taxes	(7) Income Taxes The provision for income tax consists of the following: Year Ended December 31, 2017 2016 2015 Deferred tax Federal (38 ) 55 — State 17 6 — $ (21 ) $ 61 $ — Current income tax expense for the year ended December 31, 2017 was $4 thousand and related to foreign jurisdictions. There was no current income tax expense for the years ended December 31, 2016 and 2015. Total income tax benefit for the year ended December 31, 2017 was $17 thousand. Total income tax expense for the year ended December 31, 2016 was $0.1 million. There was no current or deferred income tax (benefit) expense for the year ended December 2015. Actual income tax expense differs from that obtained by applying the statutory federal income tax rate of 34% to income before income taxes as follows (in thousands): Year Ended December 31, 2017 2016 2015 Tax at federal statutory rate $ (21,776 ) $ (13,636 ) $ (14,018 ) State, net of federal benefit (2,637 ) (1,321 ) (1,624 ) Permanent items 1,327 1,420 898 Research and development credits (53 ) — — State rate change (56 ) 87 180 Other (103 ) 9 1 Change in federal statutory rate 34,555 — — Change in valuation allowance (11,274 ) 13,502 14,563 $ (17 ) $ 61 $ — The tax effects of temporary differences and carryforwards that give rise to significant portions of the deferred tax assets are as follows (in thousands): December 31, 2017 2016 Net operating loss carryforwards $ 61,171 $ 65,626 Research and development credits 3,049 2,233 Accruals and reserves 4,993 4,362 Intangibles 5,605 8,309 74,818 80,530 Less valuation allowance (71,075 ) (80,470 ) Total deferred tax assets $ 3,743 $ 60 Depreciation $ (18 ) (60 ) Intangibles - deferred tax liability (3,663 ) — Indefinite-lived intangibles (naked credit) (102 ) (61 ) Total deferred tax liabilities (3,783 ) (121 ) Net deferred taxes $ (40 ) $ (61 ) In assessing the realizability of deferred tax assets, management considers whether it is more likely than not that some portion or all of the deferred tax assets will not be realized. Generally, the ultimate realization of deferred tax assets is dependent on the generation of future taxable income during the periods in which those temporary differences become deductible. Based on all the relevant factors, a valuation allowance of $71.1 million has been established against deferred tax assets as of December 31, 2017 as management determined that it is more likely than not that sufficient taxable income will not be generated to realize these temporary differences. Net deferred tax liabilities are recorded in warranties and other long-term liabilities in the consolidated balance sheet. As of December 31, 2017, the Company had net operating loss carryforwards of approximately $239 million and $138 million available to reduce future taxable income, if any, for federal and state income tax purposes, respectively. The federal net operating loss carryforward begins expiring in 2027, and the state net operating loss carryforwards begin expiring in 2017. It is possible that the Company will not generate taxable income in time to use these NOLs before their expiration. In addition, under Section 382 of the Internal Revenue Code of 1986, as amended, or the Code, if a corporation undergoes an “ownership change”, the corporation's ability to use its pre-change NOL carryforwards and other pre-change tax attributes to offset its post-change income may be limited. In general, an “ownership change” occurs if there is a cumulative change in a loss corporation’s ownership by 5% shareholders that exceeds 50 percentage points over a rolling three-year period. The Company has not performed a detailed analysis to determine whether an ownership change under Section 382 of the Code has previously occurred. As a result, if the Company earns net taxable income, its ability to use their pre-change net operating loss carryforwards to offset U.S. federal taxable income may become subject to limitations, which could potentially result in increased future tax liability to the Company. Until such analysis is completed, the Company cannot be sure that the full amount of the existing federal NOLs will be available to them, even if taxable income is generated before their expiration. At December 31, 2017 the Company had research and development credit carryforwards of approximately $1.9 million and $2.1 million available to reduce future taxable income, if any, for federal and California state income tax purposes, respectively. The federal credit carryforwards begin expiring in 2027 and the state credits carryforward indefinitely. At December 31, 2017, the Company had unrecognized tax benefits of approximately $1.0 million associated with the research and development credits. All of the unrecognized tax benefits that, if recognized, would affect the annual effective rate. The Company does not anticipate that total unrecognized net tax benefits will significantly change over the next twelve months. A reconciliation of the beginning and ending amount of unrecognized tax benefits is as follows (in thousands): Ending balance at December 31, 2015 $ 732 Additions based on tax positions taken in the current year — Ending balance at December 31, 2016 732 Additions based on acquisitions during the current year 186 Additions based on tax positions taken in the current year 48 Ending balance at December 31, 2017 $ 966 It is the Company’s policy to include penalties and interest expense related to income taxes as a component of other (income) expense and interest expense, respectively, as necessary. There was no interest expense or penalties related to unrecognized tax benefits recorded through December 31, 2017. The Company files U.S. federal, state and foreign income tax returns in jurisdictions with varying statutes of limitations. The years that may be subject to examination will vary by jurisdiction. The Company’s tax years 2014 to 2017 will remain open for examination by the federal and state tax authorities. The Company has adopted ASU 2016-09, Improvements to Employee Share-Based Payment Accounting On December 22, 2017, the U.S. government enacted comprehensive tax legislation commonly referred to as the Tax Cuts and Jobs Act (the “Tax Act”). The Tax Act makes broad and complex changes to the U.S. tax code, including, but not limited to, reducing the U.S. federal corporate tax rate to 21% and changing rules to allow an indefinite carryover period and a limitation of 80% of taxable income for net operating loss carryforwards created in tax years beginning after December 31, 2017. As a result and in accordance with Staff Accounting Bulletin No. 118, the Company has recorded a decrease related to its net deferred tax assets before valuation allowance of $34.6 million with a corresponding reduction in the valuation allowance .

Employee Benefit Plans

Employee Benefit Plans	12 Months Ended
	Dec. 31, 2017
Compensation And Retirement Disclosure [Abstract]
Employee Benefit Plans	(8) Employee Benefit Plans In September 2016, the Company adopted a Section 401(k) Retirement Savings Plan for the benefit of eligible employees. All employees become eligible to participate in the plan the first of the month following their hire date and may contribute their pretax or after–tax salary, up to the Internal Revenue Service annual contribution limit. The Company makes contributions to the 401(k) plan under a safe harbor provision, whereby the Company contributes 3% of each participating employee’s annual compensation. The Company contributions vest immediately. The Company contributed and included in operating expense $0.6 million and $0.1 million for the years ended December 31, 2017 and 2016, respectively.

Stockholders' Equity

Stockholders' Equity	12 Months Ended
	Dec. 31, 2017
Disclosure Of Compensation Related Costs Sharebased Payments [Abstract]
Stockholders' Equity	(9) (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 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 the 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 loan 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 December 31, 2017, 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 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 reserved for issuance under the 2007 Plan. As of December 31, 2017, pursuant to the 2007 Plan, there were 493,943 options outstanding and no shares of common stock available for future grants. 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 December 31, 2017, pursuant to the 2014 Plan, there were 2,789,442 shares of common stock reserved and 321,570 shares of common stock available for future grants. 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 December 31, 2017, inducement grants for 330,000 shares of common stock have been awarded, and 34,000 shares of common stock were reserved 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 be not 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, 2015 2,785,672 $ 6.66 6.60 Granted 571,753 7.08 Exercised (478,099 ) 1.93 Forfeited (92,349 ) 15.35 Balances at December 31, 2016 2,786,977 7.27 6.28 Granted 180,000 9.12 Exercised (480,236 ) 2.80 Forfeited (306,954 ) 13.01 Balances at December 31, 2017 2,179,787 $ 7.60 7.27 Vested and expected to vest at December 31, 2017 2,179,787 7.60 Vested and exercisable at December 31, 2017 1,336,308 $ 7.85 6.66 The weighted average grant date fair value of stock options granted to employees and directors during the years ended December 31, 2017, 2016 and 2015 was $4.54, $3.97, and $4.60 per share, respectively. Stock-based compensation expense for stock options for the years ended December 31, 2017, 2016 and 2015 was $2.2 million, $1.7 million and $2.0 million, respectively. Tax benefits arising from the disposition of certain shares issued upon exercise of stock options within two years of the date of grant or within one year of the date of exercise by the option holder, or Disqualifying Dispositions, provide the Company with a tax deduction equal to the difference between the exercise price and the fair market value of the stock on the date of exercise. As of December 31, 2017 there was $2.5 million of total unrecognized compensation cost related to stock options granted under the plans. The costs are expected to be recognized over a weighted average period of 1.98 years. The expense is recorded within the operating expense components in the consolidated statement of operations based on the employees receiving the awards. The aggregate intrinsic value of stock options is calculated as the difference between the exercise price of the stock options and the fair value of the Company’s common stock for those stock options that had exercise prices lower than the fair value of the Company’s common stock. The aggregate intrinsic value of stock options exercised was $3.1 million, $3.0 million, and $0.6 million during the years ended December 31, 2017, 2016 and 2015, respectively. The expected term of employee stock options, risk‑free interest rate and volatility represents the weighted average, based on grant date period, which the stock options are expected to remain outstanding. The Company utilized the simplified method to estimate the expected term of the options pursuant to ASC Subtopic 718‑10 for all option grants to employees. The expected volatility is based upon historical volatilities of an index of a peer group because it is not practicable to make a reasonable estimate of the Company’s volatility. The risk‑free interest rate is based on the U.S. Treasury yield curve in effect at the time of the grant for periods corresponding with the expected term of the option. The dividend yield assumption is based on the Company’s history and expectation of dividend payouts. The Company has never declared or paid any cash dividends on its common stock, and the Company does not anticipate paying any cash dividends in the foreseeable future. During the year ended December 31, 2017, the Company adopted ASU 2016-09, Compensation—Stock Compensation (Topic 718): Improvements to Employee Share-Based Payment Accounting For purposes of financial accounting for stock‑based compensation, the Company has determined the fair values of its options based in part on the work of a third‑party valuation specialist. The determination of stock‑based compensation is inherently uncertain and subjective and involves the application of valuation models and assumptions requiring the use of judgment. If the Company had made different assumptions, its stock‑based compensation expense, and its net loss could have been significantly different. (d) Restricted Stock Units The Company has issued restricted stock unit awards, or RSUs, to employees and non-employees under the 2014 Plan and Inducement Plan. The RSUs issued to employees vest on a straight-line basis, either quarterly over a 4-year requisite service period or annually over a 3-year requisite service period. The RSUs issued to non-employees are generally for consulting services and vest over the contractual service period. Activity related to RSUs is set forth below: Weighted average Number grant date of shares fair value Balances at December 31, 2015 17,993 $ 3.88 Granted 557,240 8.21 Vested (4,500 ) 3.88 Forfeited (140,000 ) 8.44 Balances at December 31, 2016 430,733 7.99 Granted 832,145 9.19 Vested (293,910 ) 7.75 Forfeited (40,416 ) 8.47 Balances at December 31, 2017 928,552 $ 9.12 The weighted average grant date fair value of RSUs granted to employees and directors during the years ended December 31, 2017, 2016 and 2015 was $9.19, $8.21, and $3.88 per share, respectively. Stock-based compensation expense for RSUs for the years ended December 31, 2017, 2016 and 2015 was $4.1 million, $1.2 million and $2 thousand, respectively. As of December 31, 2017, there was $5.7 million total unrecognized compensation cost related to non-vested RSU awards. The cost is expected to be recognized over a weighted average period of 1.89 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 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, except that the first offering period commenced on the first trading day following the effective date of the Company’s registration statement. 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 exercise date. A total of 255,500 shares of common stock were initially reserved for issuance under the ESPP. The number of shares available for sale under the ESPP will be increased annually on the first day of each fiscal year, equal to the lesser of i) 1% of the total outstanding shares of the Company’s common stock as of the last day of the immediately preceding fiscal year; ii) 3,000,000 shares of common stock, or iii) such lesser amount as determined by the board of directors. As of December 31, 2017, the number of shares of common stock reserved for issuance under the ESPP was 770,549. During the year ended December 31, 2017, employees purchased 108,081 shares under the ESPP at a weighted average exercise price of $5.98 per share. During the year ended December 31, 2016, employees purchased 122,667 shares under the ESPP at a weighted average exercise price of $6.14 per share. As of December 31, 2017, the number of shares of common stock available for future issuance under the ESPP was 495,551. Stock-based compensation related to the ESPP for the years ended December 31, 2017, 2016 and 2015 was $0.4 million, $0.3 million, and $0.4 million, respectively.

Segment Reporting and Geographi

Segment Reporting and Geographic Information	12 Months Ended
	Dec. 31, 2017
Segment Reporting [Abstract]
Segment Reporting and Geographic Information	(10) (a) 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 3a – Acquisitions for additional details. miraDry has been included in the consolidated results of operations as of the Acquisition Date and financial performance of the acquired business is reported in the miraDry segment. 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): December 31, 2017 2016 2015 Net sales Breast Product $ 31,485 $ 20,734 $ 38,106 miraDry 5,057 — — Total net sales $ 36,542 $ 20,734 $ 38,106 December 31, 2017 2016 2015 Loss from operations Breast Product $ (56,657 ) $ (40,034 ) $ (38,525 ) miraDry (6,233 ) — — Total loss from operations $ (62,890 ) $ (40,034 ) $ (38,525 ) December 31, 2017 2016 Assets Breast Product $ 59,365 $ 114,283 miraDry 32,848 — Total assets $ 92,213 $ 114,283 (b) Geographic Information Net sales are attributed to geographic areas based on where the Company’s products are shipped. The following tables present the net sales by geographical region for the periods presented (in thousands): December 31, 2017 2016 2015 United States $ 33,473 $ 20,734 $ 38,106 International 3,069 — — Total net sales $ 36,542 $ 20,734 $ 38,106

Commitments and Contingencies

Commitments and Contingencies	12 Months Ended
	Dec. 31, 2017
Commitments And Contingencies Disclosure [Abstract]
Commitments and Contingencies	(11) Commitments and Contingencies (a) Operating Lease Commitment In August 2013, the Company entered into a four-month warehouse lease in Santa Barbara, California, commencing on September 1, 2013. This operating lease is used for additional general office, warehouse, and research and development. This lease has been renewed until January 2019. In March 2014, the Company entered into a 68-month lease agreement in Santa Barbara, California. The operating lease is for general office use only and commenced on July 1, 2014. The terms of the lease provide for rental payments on a graduated scale. In December 2013, the Company entered into a 62-month non-cancelable operating lease for its office building space in Santa Clara, California, commencing on March 1, 2014. In connection with the lease, the Company entered into a letter of credit, which is secured by a restricted cash balance of $0.3 million, included in other assets on the consolidated balance sheets. The Company also has a one year operating lease for office space in Hong Kong which expires in November 2018. The Company recognizes rent expense on a straight-line basis over the lease term in operating expenses within the consolidated statement of operations. Rent expense for the years ended December 31, 2017, 2016 and 2015 was $1.1 million, $0.5 million and $0.5 million, respectively. As of December 31, 2017, future minimum lease payments under all non‑cancelable operating leases are as follows (in thousands): Year Ended December 31: 2018 $ 1,164 2019 1,034 2020 172 2021 — 2022 and thereafter — $ 2,370 (b) Contingencies The Company is subject to claims and assessments 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 ’ ’ ’ ’ ’ 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 within general and administrative expense within the consolidated statement of operations 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 insurance recovery receivable on the accompanying consolidated balance sheets. 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 agreed to further pay $1.0 million on or by July 1, 2018. In addition, should the Company enter into international markets using certain breast implant specifications, the Company has agreed to make royalty payments of $12.50 on each of its net sales of such products, up to a maximum royalty of $5.0 million. As a result of the settlement, the Company has recorded $10.0 million for the year ended December 31, 2017 in legal settlement expense. 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

Subsequent Events	12 Months Ended
	Dec. 31, 2017
Subsequent Events [Abstract]
Subsequent Events	(12) Subsequent Events Shelf Registration Statement and At-The-Market Offering of Common Stock On January 8, 2018, we filed a “shelf” registration statement on Form S-3 with the SEC, which was declared effective by the SEC on February 2, 2018. On February 20, 2018, we entered into an At-The-Market Equity Offering Sales Agreement, or the Sales Agreement, with Stifel, Nicolaus & Company, Incorporated, as sales agent, or Stifel, pursuant to which we may offer and sell, from time to time, through Stifel shares of our common stock having an aggregate gross offering price of up to $50 million. We are not obligated to sell any shares under the Sales Agreement. Subject to the terms and conditions of the Sales Agreement, Stifel will use commercially reasonable efforts consistent with its normal trading and sales practices, applicable state and federal law, rules and regulations, and the rules of the NASDAQ Global Select Market to sell shares from time to time based upon our instructions, including any price, time or size limits we specify. Under the Sales Agreement, Stifel may sell shares by any method deemed to be an “at-the-market offering” as defined in Rule 415 under the Securities Act or any other method permitted by law. Stifel’s obligations to sell shares under the Sales Agreement are subject to the satisfaction of certain conditions, including the continued effectiveness of the associated registration statement on Form S-3. We will pay Stifel a commission of 3.0% of the aggregate gross proceeds from each sale of shares occurring pursuant to the Sales Agreement, if any.

Summary of Quarterly Financial

Summary of Quarterly Financial Information (Unaudited)	12 Months Ended
	Dec. 31, 2017
Selected Quarterly Financial Information [Abstract]
Summary of Quarterly Financial Information (Unaudited)	(13) Summary of Quarterly Financial Information (Unaudited) The following tables set forth our unaudited quarterly statements of operations data and our key metrics for each of the eight quarters ended December 31, 2017. We have prepared the quarterly data on a consistent basis with the audited financial statements included in this report. In the opinion of management, the financial information reflects all necessary adjustments, consisting only of normal recurring adjustments, necessary for a fair presentation of this data. This information should be read in conjunction with the audited financial statements and related notes included elsewhere in this report. The results of historical periods are not necessarily indicative of the results of operations for a full year or any future period. Quarter Ended 2017 March 31 June 30 September 30 December 31 (in thousands, except share data) Net sales $ 7,489 $ 8,169 $ 9,819 $ 11,065 Gross profit 5,167 5,548 6,335 5,321 Net loss (11,422 ) (20,391 ) (14,381 ) (17,834 ) Net loss per share: Basic and diluted $ (0.61 ) $ (1.07 ) $ (0.74 ) $ (0.92 ) Quarter Ended 2016 March 31 June 30 September 30 December 31 (in thousands, except share data) Net sales $ 1,471 $ 6,244 $ 6,531 $ 6,488 Gross profit 711 4,499 4,717 3,927 Net loss (11,937 ) (10,193 ) (9,963 ) (8,073 ) Net loss per share: Basic and diluted $ (0.66 ) $ (0.56 ) $ (0.55 ) $ (0.43 )

Schedule II - Valuation And Qua

Schedule II - Valuation And Qualifying Accounts	12 Months Ended
	Dec. 31, 2017
Valuation And Qualifying Accounts [Abstract]
Schedule II - Valuation And Qualifying Accounts	Sientra, Inc. Schedule II — Valuation and Qualifying Accounts December 31, 2017, 2016 and 2015 (In thousands) Additions Balance at charged to Balance at beginning of costs and end of period expenses Deductions (1) period Year Ended December 31, 2015 Allowance for sales returns $ 10,018 $ 85,429 $ (94,787 ) $ 660 Year Ended December 31, 2016 Allowance for sales returns $ 660 $ 33,797 $ (30,549 ) $ 3,908 Year Ended December 31, 2017 Allowance for sales returns $ 3,908 $ 48,098 $ (48,100 ) $ 3,906 (1) Amounts represent actual sales returns.

Summary of Significant Accoun21

Summary of Significant Accounting Policies (Policies)	12 Months Ended
	Dec. 31, 2017
Accounting Policies [Abstract]
Basis of Presentation and Use of Estimates	(a) Basis of Presentation and Use of Estimates The preparation of financial statements in conformity with accounting principles generally accepted in the United States of America, or GAAP, requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities and the disclosure of contingent assets and liabilities at the dates of the financial statements, and the reported amounts of revenues and expenses during the reporting period. Actual results could differ from those estimates. Assets and liabilities which are subject to significant judgment and use of estimates include the allowance for doubtful accounts, sales return reserves, provision for warranties, valuation of inventories, recoverability of long-lived assets, valuation allowances with respect to deferred tax assets, useful lives associated with property and equipment and finite lived intangible assets, and the valuation and assumptions underlying stock-based compensation and other equity instruments. On an ongoing basis, the Company evaluates its estimates compared to historical experience and trends, which form the basis for making judgments about the carrying value of assets and liabilities. In addition, the Company engages the assistance of valuation specialists in concluding on fair value measurements in connection with stock-based compensation and other equity instruments.
Going Concern	(b) Going Concern Since inception, the Company has incurred net losses. During the years ended December 31, 2017, 2016 and 2015 the Company incurred net losses of $64.0 million, $40.2 million and $41.2 million, respectively. The Company used $45.9 million of cash in operations for the year ended December 31, 2017, $34.4 million for the year ended December 31, 2016 and $18.2 million for the year ended December 31, 2015. At December 31, 2017 and 2016 the Company had an accumulated deficit of $279.5 million and $215.4 million, respectively. At December 31, 2017, the Company had cash and cash equivalents of $26.6 million. These consolidated financial statements have been prepared assuming that the Company will continue as a going concern and do not include any adjustments that might result from the outcome of this uncertainty. The Company has incurred recurring losses from operations and cash outflows from operating activities that raise substantial doubt about its ability to continue as a going concern. In addition, while the Company was in compliance with the financial covenants in its credit agreement with MidCap Financial Trust at December 31, 2017, given the potential violations of those covenants during fiscal year 2018, the Company has classified the debt as current in the consolidated balance sheet at December 31, 2017. Management has taken and is taking actions to improve our liquidity. For example, the Company has the ability to receive a $10.0 million term loan pursuant to our credit agreement with MidCap Financial Trust, upon receipt of FDA certifications of the manufacturing facility operated by Vesta by March 31, 2018. In addition, in February 2018, the Company entered into an At-The-Market Equity Offering Sales Agreement with Stifel, Nicolaus & Company, Incorporated 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 million. In addition, the Company may raise additional capital through the sale of equity securities and incremental debt financing. While there can be no assurances that the Company will be successful in obtaining the level of financing needed for its operations, the Company believes it is probable that the actions taken, together with any additional equity or debt financing the Company may pursue, will be sufficient to address liquidity needs and alleviate the substantial doubt about the Company’s ability to continue as a going concern for a reasonable period of time. If the Company is unsuccessful in raising capital, it may need to reduce activities, curtail or cease certain operations.
Cash and Cash Equivalents	(c) Cash and Cash Equivalents The Company considers all highly liquid investments purchased with an original maturity of three months or less when purchased to be cash equivalents. Cash and cash equivalents consist primarily of cash in checking accounts and interest-bearing money market accounts.
Concentration of Credit and Supplier Risks	(d) Concentration of Credit and Supplier Risks Financial instruments that potentially subject the Company to significant concentrations of credit risk consist primarily of cash and cash equivalents. The Company’s cash and cash equivalents are deposited in demand accounts at a financial institution that management believes is creditworthy. The Company is exposed to credit risk in the event of default by this financial institution for cash and cash equivalents in excess of amounts insured by the Federal Deposit Insurance Corporation, or FDIC. Management believes that the Company’s investments in cash and cash equivalents are financially sound and have minimal credit risk and the Company has not experienced any losses on its deposits of cash and cash equivalents. The Company relies on a limited number of third-party manufacturers for the manufacturing and supply of its products. This could result in the Company not being able to acquire the inventory needed to meet customer demand, which would result in possible loss of sales and affect operating results adversely.
Fair Value of Financial Instruments	(e) Fair Value of Financial Instruments The carrying amounts of cash and cash equivalents, accounts receivable, accounts payable, accrued liabilities, and customer deposits are reasonable estimates of their fair value because of the short maturity of these items. The fair value of the common stock warrant liability, deferred and contingent consideration are discussed in Note 2. The fair value of the debt is based on the amount of future cash flows associated with the instrument discounted using the Company’s market rate. As of December 31, 2017, the carrying value of the debt is presented as a current liability of $24.6 million, representing the principal obligations, net of debt issuance costs, owed under the term loan.
Fair Value Measurements	(f) 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 deferred consideration and 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 from SSP and the deferred and 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 deferred consideration and 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 December 31, 2017 and 2016 and indicate the level of the fair value hierarchy utilized to determine such fair value (in thousands): 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 deferred consideration — — 1,255 1,255 Liability for contingent consideration — — 12,319 12,319 $ — — 13,768 13,768 Fair Value Measurements as of December 31, 2016 Using: Level 1 Level 2 Level 3 Total Liabilities: Liability for common stock warrants $ — — 99 99 Liability for deferred consideration — — 395 395 Liability for contingent consideration — — 1,242 1,242 $ — — 1,736 1,736 The liability for common stock warrants and the current portion of deferred consideration is included in “accrued and other current liabilities” and the long-term liabilities for the deferred consideration and contingent consideration are included in “deferred and contingent consideration” in the consolidated balance sheet. The following table provides a rollforward of the aggregate fair values of the Company’s common stock warrants, deferred and contingent consideration for which fair value is determined by Level 3 inputs (in thousands): Warrant Liability Balance, December 31, 2016 $ 99 Fair value of warrants to be issued upon borrowing under the SVB Loan Agreement (Note 5) 88 Warrants extinguished upon termination of SVB Loan Agreement (88 ) Change in fair value through December 31, 2017 95 Balance, December 31, 2017 $ 194 Deferred Consideration Liability Balance, December 31, 2016 $ 395 Initial fair value of acquisition-related deferred consideration 966 Change in fair value of deferred consideration (106 ) Balance, December 31, 2017 $ 1,255 Contingent Consideration Liability Balance, December 31, 2016 $ 1,242 Initial fair value of acquisition-related contingent consideration 9,946 Change in fair value of contingent consideration 1,131 Balance, December 31, 2017 $ 12,319 In connection with the acquisition of miraDry on July 25, 2017, contingent consideration of up to an aggregate of $14.0 million may be payable upon achieving certain future sales milestones and had a fair value of $10.4 million at December 31, 2017. In connection with the acquisition of the tissue expander portfolio from SSP on November 2, 2016, contingent consideration of up to an aggregate of $2.0 million may be payable upon achieving certain future sales milestones and had a fair value of $1.8 million and $1.1 million at December 31, 2017 and 2016, respectively. The Company recognizes changes in the fair value of the warrants in “other income (expense), net” in the consolidated statement of operations and changes in deferred consideration and contingent consideration are recognized in “general and administrative” expense in the consolidated statement of operations.
Property and Equipment	(g) Property and Equipment Property and equipment are stated at cost, net of accumulated depreciation. Depreciation is computed using the straight‑line method over the estimated useful life of the asset, generally three to five years. Leasehold improvements are depreciated over the shorter of the lease term or the estimated useful life of the related asset. Upon retirement or sale of an asset, the cost and related accumulated depreciation or amortization are removed from the consolidated balance sheet and any resulting gain or loss is reflected in operations in the period realized. Maintenance and repairs are charged to operations as incurred.
Goodwill and Other Intangible Assets	(h) Goodwill and Other Intangible Assets Goodwill represents the excess of the purchase price over the fair value of net assets of purchased businesses. Goodwill is not amortized, but instead is subject to impairment tests on at least an annual basis and whenever circumstances suggest that goodwill may be impaired. After the acquisition of miraDry, management began evaluating the Company as two reporting units, Breast Products and miraDry. 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 more likely than not that the fair value of a reporting unit is less than its carrying amount, the Company will recognize an impairment charge for the amount by which the carrying amount exceeds the reporting unit’s fair value. The Company tests indefinite-lived intangible assets for impairment on at least an annual basis and whenever circumstances suggest the assets may be impaired. The Company’s annual test for impairment is performed as of October 1 of each fiscal year. If indicators of impairment are present, the Company evaluates the carrying value of the intangible assets in relation to estimates of future undiscounted cash flows. If the carrying value of the intangible asset exceeds its fair value, an impairment loss is recognized in an amount equal to the difference. Judgments about the recoverability of purchased finite‑lived intangible assets are made whenever events or changes in circumstance indicate that impairment may exist. Each fiscal year the Company evaluates the estimated remaining useful lives of purchased intangible assets and whether events or changes in circumstance warrant a revision to the remaining periods of amortization. Recoverability of finite‑lived intangible assets is measured by comparison of the carrying amount of the asset to the future undiscounted cash flows the asset is expected to generate. The intangible asset is amortized to the consolidated statement of operations based on estimated cash flows generated from the intangible over its estimated life.
Impairment of Long-Lived Assets	( i ) Impairment of Long‑Lived Assets The Company’s management routinely considers whether indicators of impairment of long‑lived assets are present. If such indicators are present, management determines whether the sum of the estimated undiscounted cash flows attributable to the assets in question is less than their carrying value. If less, the Company will recognize an impairment loss based on the excess of the carrying amount of the assets over their respective fair values. Fair value is determined by discounted future cash flows, appraisals or other methods. If the assets determined to be impaired are to be held and used, the Company will recognize an impairment charge to the extent the present value of anticipated net cash flows attributable to the asset are less than the asset’s carrying value. The fair value of the asset will then become the asset’s new carrying value. There have been no impairments of long‑lived assets recorded during the years ended December 31, 2017, 2016 and 2015. The Company may record impairment losses in future periods if factors influencing its estimates change.
Business Combinations	(j) Business Combinations Business combinations are accounted for using the acquisition method of accounting. Under the acquisition method, assets acquired and liabilities assumed are recorded at their respective fair values as of the acquisition date in our financial statements. The excess of the fair value of consideration transferred over the fair value of the net assets acquired is recorded as goodwill. Contingent consideration obligations incurred in connection with a business combination are recorded at their fair values on the acquisition date and remeasured at their fair values each subsequent reporting period until the related contingencies are resolved. The resulting changes in fair values are recorded in earnings.
Segment Reporting	(k) Reportable 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. Based on the financial information presented to and reviewed by the CODM, the Company has determined that it has two reportable segments: Breast Products and miraDry.
Revenue Recognition	(l) Revenue Recognition The Company recognizes revenue related to sales of products directly to customers in markets where it has regulatory approval, net of trade discounts and allowances, provided that (i) persuasive evidence of an arrangement exists, (ii) delivery has occurred and title and risk of loss have transferred, (iii) the price is fixed or determinable and (iv) collectability is reasonably assured. Sales prices are documented in the executed sales contract or purchase order prior to shipment. The Company evaluates the creditworthiness of customers to determine that appropriate credit limits are established prior to the acceptance of an order. Revenue for extended warranties and service agreements are recognized ratably over the term of the agreement. 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 warehouse. The Company also leverages a distributor network for selling the miraDry System internationally. The Company recognizes revenue when title to the product and risk of loss transfer to customers, provided there are no remaining performance obligations required of the Company or any written matters requiring customer acceptance, which generally occurs upon shipment. Standard terms in these agreements do not allow for trial periods, rights of return, refunds, payments contingent on obtaining financing or other terms that could impact the customer’s obligation. Appropriate reserves are established for anticipated sales returns based on historical experience, recent gross sales and any notification of pending returns. For Breast Products specifically, the Company allows for the return of Breast Products from customers within six months after the original sale and records estimated sales returns as a reduction of sales in the same period revenue is recognized. Sales return provisions are calculated based upon historical experience with actual returns. 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 $3.9 million as of both December 31, 2017 and 2016, recorded net against accounts receivable in the consolidated balance sheet. Shipping and handling charges are largely provided to customers free of charge for breast products. The associated costs are viewed as part of the Company’s marketing programs and are recorded as a component of sales and marketing expense in the consolidated statement of operations as an accounting policy election. Shipping and handling charges are typically billed to the customer for sales of the miraDry Systems and are recorded as a component of cost of goods sold in the consolidated statement of operations. For the years ended 2017, 2016 and 2015 shipping costs amounted to $1.0 million, $0.6 million and $1.1 million, respectively.
Accounts Receivable and Allowance for Doubtful Accounts	(m) Accounts Receivable and Allowance for Doubtful Accounts Accounts receivable are recorded at the invoiced amount and do not bear interest. The Company maintains allowances for doubtful accounts for estimated losses resulting from the inability to collect from some of its customers. The allowances for doubtful accounts are based on the analysis of historical bad debts, customer credit‑worthiness, past transaction history with the customer, and current economic trends. If the financial condition of the Company’s customers were to deteriorate, adversely affecting their ability to make payments, additional allowances may be required. The Company has established an allowance for doubtful accounts of $0.9 million and $0.4 million as of December 31, 2017 and 2016, respectively.
Inventories and Cost of Goods Sold	(n) Inventories and Cost of Goods Sold Inventories represent raw materials, work in process and finished goods that are recorded at the lower of cost or market on a first‑in, first‑out basis, or FIFO. miraDry inventory costs are determined using a standard cost, which approximates actual cost on an average cost basis. The Company periodically assesses the recoverability of all inventories to determine whether adjustments for impairment or obsolescence are required. The Company evaluates the remaining shelf life and other general obsolescence and impairment criteria in assessing the recoverability of the Company’s inventory. The Company recognizes the cost of inventory transferred to the customer in cost of goods sold when revenue is recognized. At December 31, 2017 and 2016, approximately $1.6 million and $2.0 million, respectively, of the Company’s Breast Products segment inventory was held on consignment at doctors’ offices, clinics, and hospitals. The value and quantity at any one location is not significant.
Income Taxes	(o) Income Taxes The Company accounts for income taxes under the asset and liability method. Under this method, deferred tax assets and liabilities are determined based on the difference between the financial statement and tax bases of assets and liabilities using enacted tax rates in effect for the year in which the differences are expected to affect taxable income. Valuation allowances are established when necessary to reduce deferred tax assets to the amounts expected to be realized. The Company the Company The Company accounts for uncertain tax position in accordance with ASC 740‑10, Accounting for Uncertainty in Income Taxes
Research and Development Expenditures	(p) Research and Development Expenditures Research and development costs are charged to operating expenses as incurred. Research and development, or R&D, primarily consist of clinical expenses, regulatory expenses, product development, consulting services, outside research activities, quality control and other costs associated with the development of the Company’s products and compliance with Good Clinical Practices, or GCP, requirements. R&D expenses also include related personnel and consultant compensation and stock-based compensation expense.
Advertising	(q) Advertising Expenses related to advertising are charged to sales and marketing expense as incurred. Advertising costs were $1.8 million, $0.6 million and $1.0 million for the years ended December 31, 2017, 2016 and 2015, respectively.
Stock-Based Compensation	(r) Stock‑Based Compensation The Company applies the fair value provisions of ASC 718, Compensation — Stock Compensation The option-pricing models require the input of subjective assumptions, including the risk‑free interest rate, expected dividend yield, expected volatility and expected term, among other inputs. These estimates involve inherent uncertainties and the application of management’s judgment. If factors change and different assumptions are used, our stock‑based compensation expense could be materially different in the future. These assumptions are estimated as follows: • Risk‑free interest rate —The risk‑free interest rate is based on the yields of U.S. Treasury securities with maturities similar to the expected term of the options for each option group. • Dividend yield —We have never declared or paid any cash dividends and do not presently plan to pay cash dividends in the foreseeable future. Consequently, we used an expected dividend yield of zero. • Expected volatility —As we do not have a significant trading history for our common stock, the expected stock price volatility for our common stock was estimated by taking the average of (i) the median historic price volatility and (ii) the median of the implied volatility averages, with a three‑month lookback from the valuation date, for any trading options of industry peers based on daily price observations over a period equivalent to the expected term of the time to a liquidity event. We intend to continue to consistently apply this process using the same or similar public companies until a sufficient amount of historical information regarding the volatility of our own common stock share price becomes available. • Expected term —The expected term represents the period that our stock‑based awards are expected to be outstanding. During the year ended December 31, 2017, the Company adopted ASU 2016-09, Compensation—Stock Compensation (Topic 718): Improvements to Employee Share-Based Payment Accounting The following table presents the weighted‑average assumptions used to estimate the fair value of options granted during the periods presented: Year Ended December 31, Stock Options 2017 2016 2015 Expected term (in years) 4.47 to 6.07 5.47 to 6.07 5.27 to 6.08 Expected volatility 45 % to 56 % 51 % to 53 % 45 % to 52 % Risk-free interest rate 1.24 % to 2.45 % 1.42 % to 1.54 % 1.48 % to 1.92 % Dividend yield — — — The following table presents the weighted-average assumptions used to estimate the fair value of the stock purchase rights granted under the employee stock purchase plan: Year Ended December 31, ESPP 2017 2016 2015 Expected term (in years) 0.50 to 2.10 0.50 to 2.10 0.50 to 2.10 Expected volatility 46 % to 55 % 42 % to 58 % 42 % to 44 % Risk-free interest rate 0.08 % to 1.30 % 0.08 % to 0.85 % 0.08 % to 0.71 % Dividend yield — — —
Product Warranties	(s) Product Warranties The Company offers a limited warranty and a lifetime product replacement program for the Company’s silicone gel breast implants and a product warranty for the Company’s miraDry Systems. Under the breast implant limited warranty, the Company will reimburse patients for certain out-of-pocket costs related to revision surgeries performed within ten years from the date of implantation in a covered event. Under the breast implant lifetime product replacement program, the Company provides no-charge replacement breast implants if a patient experiences a covered event. Under the miraDry warranty, the Company currently provides a standard product warranty for the consoles, handpieces and the miraDry consumables, or bioTips. Additionally, an extended miraDry warranty may be purchased to provide additional protection of the miraDry System. The portion of the warranty provision expected to be incurred within 12 months is classified as current within accrued liabilities and other, while the remaining amount is classified as long-term within warranty reserve and other long-term liabilities The following table provides a rollforward of the accrued warranties (in thousands): Year Ended December 31, 2017 2016 Beginning balance as of January 1 $ 1,378 $ 1,332 Assumed warranty liability from acquisition 137 — Warranty costs incurred during the period (167 ) (25 ) Changes in accrual related to warranties issued during the period 301 177 Changes in accrual related to pre-existing warranties (7 ) (106 ) Balance as of December 31 $ 1,642 $ 1,378
Net Loss Per Share	(t) Net Loss Per Share December 31, 2017 2016 2015 Net loss (in thousands) $ (64,028 ) $ (40,166 ) $ (41,230 ) Weighted average common shares outstanding, basic and diluted 19,159,057 18,233,177 15,770,972 Net loss per share attributable to common stockholders $ (3.34 ) $ (2.20 ) $ (2.61 ) The Company excluded the following potentially dilutive securities, outstanding as of December 31, 2017, 2016 and 2015 from the computation of diluted net loss per share attributable to common stockholders for the years ended December 31, 2017, 2016 and 2015 because they had an anti-dilutive impact due to the net loss attributable to common stockholders incurred for the periods. December 31, 2017 2016 2015 Stock options to purchase common stock 1,867,627 2,057,296 1,967,906 Warrants for the purchase of common stock 47,710 47,710 47,710 1,915,337 2,105,006 2,015,616
Recent Accounting Pronouncements	(u) Recent Accounting Pronouncements Recently Adopted Accounting Standards In July 2015, the FASB issued ASU 2015-11, Inventory - Simplifying the Measurement of Inventory In March 2016, the FASB issued ASU 2016-09, Compensation - Stock Compensation (Topic 718). In January 2017, the FASB issued ASU 2017-04, Intangibles - Goodwill and Other (Topic 350) - Simplifying the Test for Goodwill Impairment eliminates Step 2 from the goodwill impairment test. The Recently Issued Accounting Standards In May 2014, the FASB issued ASU 2014-09, Revenue from Contracts with Customers Revenue from Contracts with Customers (Topic 606): Deferral of the Effective Date, In December 2016, the FASB issued ASU 2016-20, Technical Corrections and Improvements to Topic 606, Revenue from Contracts with Customers. ASU 2016-20 is intended to clarify and suggest improvements to the application of current standards under Topic 606 and other Topics amended by ASU 2014-09, Revenue from Contracts with Customers (Topic 606) . The effective date of ASU 2016-20 is the same as the effective date for ASU 2014-09. In February 2016, the FASB issued ASU 2016-02, Leases (Topic 842) Leases (Topic 840). In January 2017, the FASB issued ASU 2017-01, Business Combinations (Topic 805) - Clarifying the Definition of a Business . The standard The updated accounting standard will be effective for the Company beginning in fiscal year 2018. . 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
Reclassifications	(v) Reclassifications Certain reclassifications have been made to prior year amounts to conform to the current year presentation.

Summary of Significant Accoun22

Summary of Significant Accounting Policies (Tables)	12 Months Ended
	Dec. 31, 2017
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 December 31, 2017 and 2016 and indicate the level of the fair value hierarchy utilized to determine such fair value (in thousands): 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 deferred consideration — — 1,255 1,255 Liability for contingent consideration — — 12,319 12,319 $ — — 13,768 13,768 Fair Value Measurements as of December 31, 2016 Using: Level 1 Level 2 Level 3 Total Liabilities: Liability for common stock warrants $ — — 99 99 Liability for deferred consideration — — 395 395 Liability for contingent consideration — — 1,242 1,242 $ — — 1,736 1,736
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, deferred and contingent consideration for which fair value is determined by Level 3 inputs (in thousands): Warrant Liability Balance, December 31, 2016 $ 99 Fair value of warrants to be issued upon borrowing under the SVB Loan Agreement (Note 5) 88 Warrants extinguished upon termination of SVB Loan Agreement (88 ) Change in fair value through December 31, 2017 95 Balance, December 31, 2017 $ 194 Deferred Consideration Liability Balance, December 31, 2016 $ 395 Initial fair value of acquisition-related deferred consideration 966 Change in fair value of deferred consideration (106 ) Balance, December 31, 2017 $ 1,255 Contingent Consideration Liability Balance, December 31, 2016 $ 1,242 Initial fair value of acquisition-related contingent consideration 9,946 Change in fair value of contingent consideration 1,131 Balance, December 31, 2017 $ 12,319
Schedule of rollforward of the accrued warranties	The following table provides a rollforward of the accrued warranties (in thousands): Year Ended December 31, 2017 2016 Beginning balance as of January 1 $ 1,378 $ 1,332 Assumed warranty liability from acquisition 137 — Warranty costs incurred during the period (167 ) (25 ) Changes in accrual related to warranties issued during the period 301 177 Changes in accrual related to pre-existing warranties (7 ) (106 ) Balance as of December 31 $ 1,642 $ 1,378
Schedule of net loss per share, basic and diluted	December 31, 2017 2016 2015 Net loss (in thousands) $ (64,028 ) $ (40,166 ) $ (41,230 ) Weighted average common shares outstanding, basic and diluted 19,159,057 18,233,177 15,770,972 Net loss per share attributable to common stockholders $ (3.34 ) $ (2.20 ) $ (2.61 )
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 December 31, 2017, 2016 and 2015 from the computation of diluted net loss per share attributable to common stockholders for the years ended December 31, 2017, 2016 and 2015 because they had an anti-dilutive impact due to the net loss attributable to common stockholders incurred for the periods. December 31, 2017 2016 2015 Stock options to purchase common stock 1,867,627 2,057,296 1,967,906 Warrants for the purchase of common stock 47,710 47,710 47,710 1,915,337 2,105,006 2,015,616
Stock Option
Schedule of fair value of employee stock options estimated using Black-Scholes option valuation model	The following table presents the weighted‑average assumptions used to estimate the fair value of options granted during the periods presented: Year Ended December 31, Stock Options 2017 2016 2015 Expected term (in years) 4.47 to 6.07 5.47 to 6.07 5.27 to 6.08 Expected volatility 45 % to 56 % 51 % to 53 % 45 % to 52 % Risk-free interest rate 1.24 % to 2.45 % 1.42 % to 1.54 % 1.48 % to 1.92 % Dividend yield — — —
Employee Stock Purchase Plan
Schedule of fair value of employee stock options estimated using Black-Scholes option valuation model	The following table presents the weighted-average assumptions used to estimate the fair value of the stock purchase rights granted under the employee stock purchase plan: Year Ended December 31, ESPP 2017 2016 2015 Expected term (in years) 0.50 to 2.10 0.50 to 2.10 0.50 to 2.10 Expected volatility 46 % to 55 % 42 % to 58 % 42 % to 44 % Risk-free interest rate 0.08 % to 1.30 % 0.08 % to 0.85 % 0.08 % to 0.71 % Dividend yield — — —

Acquisitions (Tables)

Acquisitions (Tables)	12 Months Ended
	Dec. 31, 2017
miraDry
Business Acquisition [Line Items]
Schedule of aggregate preliminary acquisition date fair value of consideration transferred	The aggregate preliminary 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 preliminary 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 method 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 consolidated results of operations of the combined business had the merger actually occurred at the beginning of fiscal year 2016 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): December 31, 2017 2016 Pro Forma Net sales $ 46,747 $ 41,179 Net loss (69,545 ) (69,226 ) Pro forma loss per share attributable to ordinary shares - basic and diluted $ (3.62 ) $ (3.78 )
U.S. Rights to BIOCORNEUM
Business Acquisition [Line Items]
Schedule of aggregate preliminary acquisition date fair value of consideration transferred	The aggregate acquisition date fair value of the consideration transferred was approximately $7.4 million, which consisted of the following (in thousands): Fair Value Cash $ 6,859 Deferred consideration 434 Contingent consideration 116 $ 7,409
Schedule of allocation of the fair value of the consideration transferred by major class	The following table summarizes the allocation of the fair value of the consideration transferred by major class for the business combination completed on March 9, 2016 (in thousands): March 9, 2016 Inventories, net $ 100 Prepaid expenses 36 Goodwill 3,273 Intangible assets 4,000 $ 7,409
Schedule of intangible assets acquired	A summary of the intangible assets acquired, estimated useful lives and amortization method is as follows (in thousands): Estimated useful Amortization Amount life (in years) method Customer relationships $ 3,200 10 Accelerated Trade name 800 12 Straight-line $ 4,000
Tissue Expander Portfolio from SSP
Business Acquisition [Line Items]
Schedule of aggregate preliminary acquisition date fair value of consideration transferred	The aggregate acquisition date fair value of the consideration transferred was approximately $6.0 million, which consisted of the following (in thousands): Fair Value Cash $ 4,950 Contingent consideration 1,050 $ 6,000
Schedule of allocation of the fair value of the consideration transferred by major class	The following table summarizes the allocation of the fair value of the consideration transferred by major class for the business combination completed on November 2, 2016 (in thousands): November 2, 2016 Accounts receivable, net $ 196 Inventories, net 1,555 Equipment 34 Goodwill 1,605 Intangible assets 2,860 Liabilities assumed (250 ) $ 6,000
Schedule of intangible assets acquired	A summary of the intangible assets acquired, estimated useful lives and amortization method is as follows (in thousands): Estimated useful Amortization Amount life method Customer relationships $ 1,740 9 years Accelerated Regulatory approvals 670 14 months Straight-line Trade names 450 indefinite-lived $ 2,860

Balance Sheet Components (Table

Balance Sheet Components (Tables)	12 Months Ended
	Dec. 31, 2017
Balance Sheet Related Disclosures [Abstract]
Schedule of inventories, net	Inventories, net consist of the following (in thousands): December 31, 2017 2016 Raw materials $ 1,642 $ — Work in progress 3,956 — Finished goods 15,298 18,484 $ 20,896 $ 18,484
Schedule of property and equipment, net	Property and equipment, net consist of the following (in thousands): December 31, 2017 2016 Leasehold improvements $ 402 $ 86 Manufacturing equipment and toolings 4,260 2,264 Computer equipment 387 287 Software 797 669 Office equipment 142 129 Furniture and fixtures 816 743 6,804 4,178 Less accumulated depreciation (2,041 ) (1,192 ) $ 4,763 $ 2,986
Schedule of accrued and other current liabilities	Accrued and other current liabilities consist of the following: December 31, 2017 2016 Payroll and related expenses $ 3,579 $ 2,592 Accrued commissions 3,297 1,222 Accrued equipment 1,091 887 Deferred consideration, current portion 977 — Audit, consulting and legal fees 920 803 Accrued sales and marketing expenses 794 39 Other 2,816 964 $ 13,474 $ 6,507

Goodwill and Other Intangible25

Goodwill and Other Intangible Assets, net (Tables)	12 Months Ended
	Dec. 31, 2017
Goodwill And Intangible Assets Disclosure [Abstract]
Schedule of Changes in Carrying Amount of Goodwill	The changes in the carrying amount of goodwill during the years ended December 31, 2017 and 2016 were as follows (in thousands): Balances as of December 31, 2015 Breast Product miraDry Total Goodwill $ 14,278 $ — $ 14,278 Accumulated impairment losses (14,278 ) — (14,278 ) Goodwill, net $ — $ — $ — Goodwill acquired 4,878 — 4,878 Balances as of December 31, 2016 Goodwill $ 19,156 $ — $ 19,156 Accumulated impairment losses (14,278 ) — (14,278 ) Goodwill, net $ 4,878 $ — $ 4,878 Goodwill acquired (Note 3) — 7,629 7,629 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
Components of Other Intangible Assets	The components of the Company’s other intangible assets consist of the following definite-lived and indefinite-lived assets (in thousands): 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 December 31, 2016 Average Amortization Period Gross Carrying Accumulated Intangible (in years) Amount Amortization Assets, net Intangibles with definite lives Customer relationships 10 $ 4,940 $ (602 ) $ 4,338 Trade names - finite life 12 800 (56 ) 744 Regulatory approvals 1 670 (96 ) 574 Non-compete agreement 2 80 (17 ) 63 Acquired FDA non-gel product approval 11 1,713 (1,696 ) 17 Total definite-lived intangible assets $ 8,203 $ (2,467 ) $ 5,736 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 intangible assets as of December 31, 2017 (in thousands): Amortization Period Expense 2018 $ 2,308 2019 2,321 2020 2,209 2021 1,996 2022 1,762 Thereafter 7,757 $ 18,353

Income Taxes (Tables)

Income Taxes (Tables)	12 Months Ended
	Dec. 31, 2017
Income Tax Disclosure [Abstract]
Schedule of Provision for Income Tax	The provision for income tax consists of the following: Year Ended December 31, 2017 2016 2015 Deferred tax Federal (38 ) 55 — State 17 6 — $ (21 ) $ 61 $ —
Schedule of Reconciliation of Actual Income Tax Expense Obtained by Applying Statutory Federal Income Tax Rate	Actual income tax expense differs from that obtained by applying the statutory federal income tax rate of 34% to income before income taxes as follows (in thousands): Year Ended December 31, 2017 2016 2015 Tax at federal statutory rate $ (21,776 ) $ (13,636 ) $ (14,018 ) State, net of federal benefit (2,637 ) (1,321 ) (1,624 ) Permanent items 1,327 1,420 898 Research and development credits (53 ) — — State rate change (56 ) 87 180 Other (103 ) 9 1 Change in federal statutory rate 34,555 — — Change in valuation allowance (11,274 ) 13,502 14,563 $ (17 ) $ 61 $ —
Schedule of Tax Effects of Temporary Differences and Carryforwards that Give Rise to Significant Portions of Deferred Tax Assets	The tax effects of temporary differences and carryforwards that give rise to significant portions of the deferred tax assets are as follows (in thousands): December 31, 2017 2016 Net operating loss carryforwards $ 61,171 $ 65,626 Research and development credits 3,049 2,233 Accruals and reserves 4,993 4,362 Intangibles 5,605 8,309 74,818 80,530 Less valuation allowance (71,075 ) (80,470 ) Total deferred tax assets $ 3,743 $ 60 Depreciation $ (18 ) (60 ) Intangibles - deferred tax liability (3,663 ) — Indefinite-lived intangibles (naked credit) (102 ) (61 ) Total deferred tax liabilities (3,783 ) (121 ) Net deferred taxes $ (40 ) $ (61 )
Schedule of Reconciliation of Beginning and Ending Amount of Unrecognized Tax Benefits	A reconciliation of the beginning and ending amount of unrecognized tax benefits is as follows (in thousands): Ending balance at December 31, 2015 $ 732 Additions based on tax positions taken in the current year — Ending balance at December 31, 2016 732 Additions based on acquisitions during the current year 186 Additions based on tax positions taken in the current year 48 Ending balance at December 31, 2017 $ 966

Stockholders' Equity (Tables)

Stockholders' Equity (Tables)	12 Months Ended
	Dec. 31, 2017
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, 2015 2,785,672 $ 6.66 6.60 Granted 571,753 7.08 Exercised (478,099 ) 1.93 Forfeited (92,349 ) 15.35 Balances at December 31, 2016 2,786,977 7.27 6.28 Granted 180,000 9.12 Exercised (480,236 ) 2.80 Forfeited (306,954 ) 13.01 Balances at December 31, 2017 2,179,787 $ 7.60 7.27 Vested and expected to vest at December 31, 2017 2,179,787 7.60 Vested and exercisable at December 31, 2017 1,336,308 $ 7.85 6.66
Summary of RSUs activity	Weighted average Number grant date of shares fair value Balances at December 31, 2015 17,993 $ 3.88 Granted 557,240 8.21 Vested (4,500 ) 3.88 Forfeited (140,000 ) 8.44 Balances at December 31, 2016 430,733 7.99 Granted 832,145 9.19 Vested (293,910 ) 7.75 Forfeited (40,416 ) 8.47 Balances at December 31, 2017 928,552 $ 9.12

Segment Reporting and Geograp28

Segment Reporting and Geographic Information (Tables)	12 Months Ended
	Dec. 31, 2017
Segment Reporting [Abstract]
Summary of Net Sales and Net Operating Loss 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): December 31, 2017 2016 2015 Net sales Breast Product $ 31,485 $ 20,734 $ 38,106 miraDry 5,057 — — Total net sales $ 36,542 $ 20,734 $ 38,106 December 31, 2017 2016 2015 Loss from operations Breast Product $ (56,657 ) $ (40,034 ) $ (38,525 ) miraDry (6,233 ) — — Total loss from operations $ (62,890 ) $ (40,034 ) $ (38,525 )
Summary of Net Sales by Geographical Regions	The following tables present the net sales by geographical region for the periods presented (in thousands): December 31, 2017 2016 2015 United States $ 33,473 $ 20,734 $ 38,106 International 3,069 — — Total net sales $ 36,542 $ 20,734 $ 38,106

Commitments and Contingencies (

Commitments and Contingencies (Tables)	12 Months Ended
	Dec. 31, 2017
Commitments And Contingencies Disclosure [Abstract]
Schedule of Future Minimum Lease Payments under Non-cancelable Operating Leases	As of December 31, 2017, future minimum lease payments under all non‑cancelable operating leases are as follows (in thousands): Year Ended December 31: 2018 $ 1,164 2019 1,034 2020 172 2021 — 2022 and thereafter — $ 2,370

Summary of Quarterly Financia30

Summary of Quarterly Financial Information (Unaudited) (Tables)	12 Months Ended
	Dec. 31, 2017
Selected Quarterly Financial Information [Abstract]
Summary of Quarterly Financial Information (Unaudited)	Quarter Ended 2017 March 31 June 30 September 30 December 31 (in thousands, except share data) Net sales $ 7,489 $ 8,169 $ 9,819 $ 11,065 Gross profit 5,167 5,548 6,335 5,321 Net loss (11,422 ) (20,391 ) (14,381 ) (17,834 ) Net loss per share: Basic and diluted $ (0.61 ) $ (1.07 ) $ (0.74 ) $ (0.92 ) Quarter Ended 2016 March 31 June 30 September 30 December 31 (in thousands, except share data) Net sales $ 1,471 $ 6,244 $ 6,531 $ 6,488 Gross profit 711 4,499 4,717 3,927 Net loss (11,937 ) (10,193 ) (9,963 ) (8,073 ) Net loss per share: Basic and diluted $ (0.66 ) $ (0.56 ) $ (0.55 ) $ (0.43 )

Formation and Business of the31

Formation and Business of the Company (Details)	Jun. 11, 2017USD ($)Payment$ / shares	Sep. 23, 2015USD ($)$ / sharesshares	Dec. 31, 2017	Dec. 31, 2015shares
Miramar Labs, Inc.,
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
Effective date of acquisition			Jul. 25, 2017
Minimum | Miramar Labs, Inc.,
Formation and Business of the Company [Line Items]
Number of contingent payments | Payment	1
Maximum | Miramar Labs, Inc.,
Formation and Business of the Company [Line Items]
Business combination, potential contingent payments	$ 14,000,000
Common stock
Formation and Business of the Company [Line Items]
Proceeds from IPO/follow-on offering, net of costs (in shares) | shares				3,000,000
Common stock | Follow-On Offering
Formation and Business of the Company [Line Items]
Proceeds from IPO/follow-on offering, net of costs (in shares) | shares		3,000,000
Public offering price (in dollars per share) | $ / shares		$ 22
Proceeds from the issuance of common stock, net of underwriting discounts, commissions and offering expenses		$ 61,400,000
Payment of underwriting discounts and commissions and offering expenses		4,000,000
Offering expenses		$ 600,000

Summary of Significant Accoun32

Summary of Significant Accounting Policies (Details)	Jan. 02, 2017USD ($)	Jan. 02, 2016USD ($)	Feb. 28, 2018USD ($)	Dec. 31, 2017USD ($)	Sep. 30, 2017USD ($)	Jun. 30, 2017USD ($)	Mar. 31, 2017USD ($)	Dec. 31, 2016USD ($)	Sep. 30, 2016USD ($)	Jun. 30, 2016USD ($)	Mar. 31, 2016USD ($)	Dec. 31, 2017USD ($)ReportingUnitSegment	Dec. 31, 2016USD ($)	Dec. 31, 2015USD ($)	Jul. 25, 2017USD ($)	Nov. 02, 2016USD ($)	Dec. 31, 2014USD ($)
Summary Of Significant Accounting Policies [Line Items]
Net loss				$ (17,834,000)	$ (14,381,000)	$ (20,391,000)	$ (11,422,000)	$ (8,073,000)	$ (9,963,000)	$ (10,193,000)	$ (11,937,000)	$ (64,028,000)	$ (40,166,000)	$ (41,230,000)
Cash in operations												(45,916,000)	(34,430,000)	(18,184,000)
Accumulated deficit				(279,470,000)				(215,442,000)				(279,470,000)	(215,442,000)
Cash and cash equivalents				26,588,000				67,212,000				26,588,000	67,212,000	$ 112,801,000			$ 96,729,000
Carrying value of debt, current				24,639,000								$ 24,639,000
Estimated dividend yield												0.00%
Segment Information
Number of reporting units | ReportingUnit												2
Number of reportable segments | Segment												2
Product Warranties
Period to claim reimbursement under limited warranty program												10 years
Accounting Standards Update 2016-09
Summary Of Significant Accounting Policies [Line Items]
Accumulated deficit	$ 0			0								$ 0
Cumulative excess benefits related to share based compensation												100,000
Deferred Tax Assets And Valuation Allowance | Accounting Standards Update 2016-09
Summary Of Significant Accounting Policies [Line Items]
Excess benefits reclassified to net operating loss carryover, resulting in increase deferred tax assets and valuation allowance	$ 100,000	$ 100,000
miraDry
Summary Of Significant Accounting Policies [Line Items]
Contingent consideration, payable															$ 14,000,000
Fair value of contingent consideration				10,400,000								10,400,000
Tissue Expander Portfolio from SSP
Summary Of Significant Accounting Policies [Line Items]
Contingent consideration, payable																$ 2,000,000
Fair value of contingent consideration				1,800,000				$ 1,100,000				1,800,000	$ 1,100,000
Subsequent Event | Maximum
Summary Of Significant Accounting Policies [Line Items]
Aggregate gross offering price			$ 50,000,000
March Two Thousand Eighteen Term Loan
Summary Of Significant Accounting Policies [Line Items]
Line of Credit Facility, Remaining Borrowing Capacity				$ 10,000,000								$ 10,000,000			$ 10,000,000

Summary of Significant Accoun33

Summary of Significant Accounting Policies - Schedule of Company's liabilities that are measured at fair value on a recurring basis ( (Details) - Recurring - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2016
Fair Value Measurements
Fair value liability	$ 13,768	$ 1,736
Warrants
Fair Value Measurements
Fair value liability	194	99
Deferred Consideration Liability
Fair Value Measurements
Fair value liability	1,255	395
Contingent Consideration Liability
Fair Value Measurements
Fair value liability	12,319	1,242
Level 3
Fair Value Measurements
Fair value liability	13,768	1,736
Level 3 | Warrants
Fair Value Measurements
Fair value liability	194	99
Level 3 | Deferred Consideration Liability
Fair Value Measurements
Fair value liability	1,255	395
Level 3 | Contingent Consideration Liability
Fair Value Measurements
Fair value liability	$ 12,319	$ 1,242

Summary of Significant Accoun34

Summary of Significant Accounting Policies - 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	12 Months Ended
	Dec. 31, 2017USD ($)
Warrants
Fair values of the Company's liabilities determined by Level 3 inputs
Balance at beginning of the period	$ 99
Fair value of warrants to be issued upon borrowing / Initial fair value of acquisition related consideration	88
Warrants extinguished upon termination of SVB Loan Agreement	(88)
Change in fair value	95
Balance at the end of the period	194
Deferred Consideration Liability
Fair values of the Company's liabilities determined by Level 3 inputs
Balance at beginning of the period	395
Fair value of warrants to be issued upon borrowing / Initial fair value of acquisition related consideration	966
Change in fair value	(106)
Balance at the end of the period	1,255
Contingent Consideration Liability
Fair values of the Company's liabilities determined by Level 3 inputs
Balance at beginning of the period	1,242
Fair value of warrants to be issued upon borrowing / Initial fair value of acquisition related consideration	9,946
Change in fair value	1,131
Balance at the end of the period	$ 12,319

Summary of Significant Accoun35

Summary of Significant Accounting Policies (PPE and Revenue) (Details) - USD ($)	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Property, Plant and Equipment
Impairment of long-lived assets	$ 0	$ 0	$ 0
Revenue Recognition
Period for sales return	6 months
Allowance for sales returns	$ 3,900,000	3,900,000
Shipping and handling charges	1,000,000	600,000	1,100,000
Accounts Receivable and Allowance for Doubtful Accounts
Allowance for doubtful accounts	900,000	400,000
Inventories and Cost of Goods Sold
Tax expense (or benefit)	(17,000)	61,000	0
Advertising
Advertising costs	1,800,000	600,000	$ 1,000,000
Breast Products
Inventories and Cost of Goods Sold
Inventory held on consignment at doctors' offices, clinics, and hospitals	$ 1,600,000	$ 2,000,000
Minimum
Property, Plant and Equipment
Estimated useful life of asset	3 years
Inventories and Cost of Goods Sold
Percentage of largest amount of tax benefit of settled uncertain tax position	50.00%
Maximum
Property, Plant and Equipment
Estimated useful life of asset	5 years

Summary of Significant Accoun36

Summary of Significant Accounting Policies - Schedule of fair value of employee stock options estimated using Black-Scholes option valuation model (Details)	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Assumptions used to estimate the fair value of stock options
Estimated dividend yield	0.00%
Stock Option
Assumptions used to estimate the fair value of stock options
Expected volatility, minimum (as a percent)	45.00%	51.00%	45.00%
Expected volatility, maximum (as a percent)	56.00%	53.00%	52.00%
Risk-free interest rate, minimum (as a percent)	1.24%	1.42%	1.48%
Risk-free interest rate, maximum (as a percent)	2.45%	1.54%	1.92%
Stock Option | Minimum
Assumptions used to estimate the fair value of stock options
Expected term (in years)	4 years 5 months 19 days	5 years 5 months 20 days	5 years 3 months 7 days
Stock Option | Maximum
Assumptions used to estimate the fair value of stock options
Expected term (in years)	6 years 26 days	6 years 26 days	6 years 30 days
Employee Stock Purchase Plan
Assumptions used to estimate the fair value of stock options
Expected volatility, minimum (as a percent)	46.00%	42.00%	42.00%
Expected volatility, maximum (as a percent)	55.00%	58.00%	44.00%
Risk-free interest rate, minimum (as a percent)	0.08%	0.08%	0.08%
Risk-free interest rate, maximum (as a percent)	1.30%	0.85%	0.71%
Employee Stock Purchase Plan | Minimum
Assumptions used to estimate the fair value of stock options
Expected term (in years)	6 months	6 months	6 months
Employee Stock Purchase Plan | Maximum
Assumptions used to estimate the fair value of stock options
Expected term (in years)	2 years 1 month 6 days	2 years 1 month 6 days	2 years 1 month 6 days

Summary of Significant Accoun37

Summary of Significant Accounting Policies - Schedule of rollforward of the accrued warranties (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016
Product Warranties
Beginning balance	$ 1,378	$ 1,332
Assumed warranty liability from acquisition	137
Warranty costs incurred during the period	(167)	(25)
Changes in accrual related to warranties issued during the period	301	177
Changes in accrual related to pre-existing warranties	(7)	(106)
Ending Balance	$ 1,642	$ 1,378

Summary of Significant Accoun38

Summary of Significant Accounting Policies - Schedule of net loss per share, basic and diluted (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2016	Sep. 30, 2016	Jun. 30, 2016	Mar. 31, 2016	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Accounting Policies [Abstract]
Net loss	$ (17,834)	$ (14,381)	$ (20,391)	$ (11,422)	$ (8,073)	$ (9,963)	$ (10,193)	$ (11,937)	$ (64,028)	$ (40,166)	$ (41,230)
Weighted average common shares outstanding, basic and diluted									19,159,057	18,233,177	15,770,972
Net loss per share attributable to common stockholders	$ (0.92)	$ (0.74)	$ (1.07)	$ (0.61)	$ (0.43)	$ (0.55)	$ (0.56)	$ (0.66)	$ (3.34)	$ (2.20)	$ (2.61)

Summary of Significant Accoun39

Summary of Significant Accounting Policies - Schedule of potentially dilutive securities excluded from the computation of diluted net loss per share attributable to common stockholders (Details) - shares	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Potentially dilutive securities
Potentially dilutive securities	1,915,337	2,105,006	2,015,616
Stock options to purchase common stock
Potentially dilutive securities
Potentially dilutive securities	1,867,627	2,057,296	1,967,906
Warrants for the purchase of common stock
Potentially dilutive securities
Potentially dilutive securities	47,710	47,710	47,710

Acquisitions (Details)

Acquisitions (Details)	Jan. 01, 2024	Jun. 11, 2017USD ($)Payment$ / shares	Nov. 02, 2016USD ($)	Mar. 09, 2016USD ($)	Dec. 31, 2017USD ($)	Dec. 31, 2016USD ($)
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
Fair value of consideration transferred		$ 29,572,000
Business combination contingent consideration payment period		1 year
U.S. Rights to BIOCORNEUM
Business Acquisition [Line Items]
Cash				$ 6,859,000
Contingent consideration				116,000
Fair value of consideration transferred				$ 7,409,000
U.S. Rights to BIOCORNEUM | Forecast
Business Acquisition [Line Items]
Number of years for future royalty payments to be paid	4 years 6 months
Tissue Expander Portfolio from SSP
Business Acquisition [Line Items]
Cash			$ 4,950,000
Contingent consideration			1,050,000
Fair value of consideration transferred			$ 6,000,000
Minimum | miraDry
Business Acquisition [Line Items]
Number of contingent payments | Payment		1
Minimum | U.S. Rights to BIOCORNEUM
Business Acquisition [Line Items]
Estimated future payments due					$ 500,000
Maximum | miraDry
Business Acquisition [Line Items]
Contingent consideration		$ 14,000,000
Estimated future payments due		$ 14,000,000
Maximum | Tissue Expander Portfolio from SSP
Business Acquisition [Line Items]
Estimated future payments due					2,000,000
General & administrative expense | miraDry
Business Acquisition [Line Items]
Professional fees					3,100,000
General & administrative expense | U.S. Rights to BIOCORNEUM
Business Acquisition [Line Items]
Professional fees						$ 200,000
General & administrative expense | Tissue Expander Portfolio from SSP
Business Acquisition [Line Items]
Professional fees					$ 100,000

Acquisitions - Schedule of aggr

Acquisitions - Schedule of aggregate preliminary acquisition date fair value of consideration transferred (Details) - USD ($) $ in Thousands	Jun. 11, 2017	Nov. 02, 2016	Mar. 09, 2016
miraDry
Business Acquisition [Line Items]
Cash consideration at Acquisition Date (other than debt payoff)	$ 6,193
Cash consideration at Acquisition Date (debt payoff)	12,467
Cash	18,700
Deferred consideration	966
Contingent consideration	9,946
Total purchase consideration	$ 29,572
U.S. Rights to BIOCORNEUM
Business Acquisition [Line Items]
Cash			$ 6,859
Deferred consideration			434
Contingent consideration			116
Total purchase consideration			$ 7,409
Tissue Expander Portfolio from SSP
Business Acquisition [Line Items]
Cash		$ 4,950
Contingent consideration		1,050
Total purchase consideration		$ 6,000

Acquisitions - Schedule of allo

Acquisitions - Schedule of allocation of the fair value of the consideration transferred by major class (Details) - USD ($) $ in Thousands	Dec. 31, 2017	Jul. 25, 2017	Dec. 31, 2016	Nov. 02, 2016	Mar. 09, 2016
Fair value of the assets acquired
Goodwill	$ 12,507		$ 4,878
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
Inventories, net		$ 7,064
U.S. Rights to BIOCORNEUM
Fair value of the assets acquired
Inventories, net					$ 100
Prepaid expenses					36
Goodwill					3,273
Intangible assets					4,000
Liabilities assumed:
Net assets acquired					7,409
Inventories, net					$ 100
Tissue Expander Portfolio from SSP
Fair value of the assets acquired
Accounts receivable, net				$ 196
Inventories, net				1,555
Equipment				34
Goodwill				1,605
Intangible assets				2,860
Liabilities assumed:
Liabilities assumed				(250)
Net assets acquired				6,000
Inventories, net				$ 1,555

Acquisitions - Schedule of inta

Acquisitions - Schedule of intangible assets acquired (Details) - USD ($) $ in Thousands	Jul. 25, 2017	Nov. 02, 2016	Mar. 09, 2016
Tissue Expander Portfolio from SSP | Trade name
Fair value of the assets acquired
Intangible assets		$ 450
Developed technology | miraDry
Fair value of the assets acquired
Intangible assets	$ 3,000
Estimated useful life of asset	15 years
Amortization method	Accelerated
Customer relationships | miraDry
Fair value of the assets acquired
Intangible assets	$ 6,300
Estimated useful life of asset	14 years
Amortization method	Accelerated
Customer relationships | U.S. Rights to BIOCORNEUM
Fair value of the assets acquired
Intangible assets			$ 3,200
Estimated useful life of asset			10 years
Amortization method			Accelerated
Customer relationships | Tissue Expander Portfolio from SSP
Fair value of the assets acquired
Intangible assets		$ 1,740
Estimated useful life of asset		9 years
Amortization method		Accelerated
Distributor relationships | miraDry
Fair value of the assets acquired
Intangible assets	$ 500
Estimated useful life of asset	9 years
Amortization method	Accelerated
Trade name | miraDry
Fair value of the assets acquired
Intangible assets	$ 5,000
Estimated useful life of asset	15 years
Amortization method	Accelerated
Trade name | U.S. Rights to BIOCORNEUM
Fair value of the assets acquired
Intangible assets			$ 800
Estimated useful life of asset			12 years
Amortization method			Straight-line
Regulatory approvals | Tissue Expander Portfolio from SSP
Fair value of the assets acquired
Intangible assets		$ 670
Estimated useful life of asset		14 months
Amortization method		Straight-line

Acquisitions - Unaudited Pro Fo

Acquisitions - Unaudited Pro Forma Information (Details) - miraDry - USD ($) $ / shares in Units, $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016
Business Acquisition [Line Items]
Net sales	$ 46,747	$ 41,179
Net loss	$ (69,545)	$ (69,226)
Pro forma loss per share attributable to ordinary shares - basic and diluted	$ (3.62)	$ (3.78)

Balance Sheet Components (Inven

Balance Sheet Components (Inventories) (Details) - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2016
Balance Sheet Related Disclosures [Abstract]
Raw materials	$ 1,642
Work in progress	3,956
Finished goods	15,298	$ 18,484
Inventory, net	$ 20,896	$ 18,484

Balance Sheet Components (PPE)

Balance Sheet Components (PPE) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Property Plant And Equipment [Line Items]
Property and equipment, gross	$ 6,804	$ 4,178
Less accumulated depreciation	(2,041)	(1,192)
Property and equipment, net	4,763	2,986
Depreciation expense	900	400	$ 300
Leasehold improvements
Property Plant And Equipment [Line Items]
Property and equipment, gross	402	86
Manufacturing equipment and toolings
Property Plant And Equipment [Line Items]
Property and equipment, gross	4,260	2,264
Computer equipment
Property Plant And Equipment [Line Items]
Property and equipment, gross	387	287
Software
Property Plant And Equipment [Line Items]
Property and equipment, gross	797	669
Office equipment
Property Plant And Equipment [Line Items]
Property and equipment, gross	142	129
Furniture and fixtures
Property Plant And Equipment [Line Items]
Property and equipment, gross	$ 816	$ 743

Balance Sheet Components (Accru

Balance Sheet Components (Accrued liabilities) (Details) - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2016
Accrued and other current liabilities
Payroll and related expenses	$ 3,579	$ 2,592
Accrued commissions	3,297	1,222
Accrued equipment	1,091	887
Deferred consideration, current portion	977
Audit, consulting and legal fees	920	803
Accrued sales and marketing expenses	794	39
Other	2,816	964
Total	$ 13,474	$ 6,507

Debt and Revolving Loan (Detail

Debt and Revolving Loan (Details) - USD ($)	Jul. 25, 2017	Dec. 31, 2017
Line Of Credit Facility [Line Items]
Credit and security agreement entered date	Jul. 25, 2017
Repayment of indebtedness	$ 5,000,000
Amortization of debt issuance costs		$ 100,000
Additional interest (as a percent)	5.00%
Term Loans
Line Of Credit Facility [Line Items]
Future debt payments		25,000,000
Loan Agreement With Silicon Valley Bank
Line Of Credit Facility [Line Items]
Extinguishment of warrants forgiven	$ 100,000
Loan Agreement With Silicon Valley Bank | Interest Expense
Line Of Credit Facility [Line Items]
Write-off of related issuance costs	16,000
Loan Agreement With Silicon Valley Bank | Long Term Liabilities
Line Of Credit Facility [Line Items]
Commitment fee payable forgiven	800,000
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	Mar. 31, 2018
Debt scheduled maturity date	Dec. 1, 2021
Origination fee (as a percent)	0.50%
Loan amount outstanding	$ 40,000,000	25,000,000
Unamortized debt issuance costs on term loan, current portion		$ 300,000
Term Loan Credit Agreement | London Interbank Offered Rate (LIBOR)
Line Of Credit Facility [Line Items]
Debt Instrument Reference Rate		1.36%
Spread on variable rate basis (as a percent)		7.50%
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	$ 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]
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. 1, 2021
Origination fee (as a percent)	0.50%
Loan amount outstanding	$ 10,000,000	0
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 | 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%
Revolving Credit Agreement | Prepaid Expenses and Other Current Assets
Line Of Credit Facility [Line Items]
Unamortized debt issuance costs on term loan, current portion		$ 100,000

Goodwill and Intangible Assets

Goodwill and Intangible Assets (Details) $ in Thousands	12 Months Ended
	Dec. 31, 2017USD ($)ReportingUnit	Dec. 31, 2016USD ($)	Dec. 31, 2015USD ($)
Goodwill And Intangible Assets Disclosure [Abstract]
Number of reporting units | ReportingUnit	2
Goodwill impairment			$ 14,278
Amortization expense	$ 2,200	$ 800	$ 100

Goodwill and Intangible Asset50

Goodwill and Intangible Assets - Schedule of Changes in Carrying Amount of Goodwill (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2017
Goodwill and intangible assets
Goodwill	$ 19,156	$ 14,278	$ 26,785
Accumulated impairment losses	(14,278)	(14,278)	(14,278)
Goodwill, net	4,878		12,507
Goodwill acquired	7,629	4,878
Breast Product
Goodwill and intangible assets
Goodwill	19,156	14,278	19,156
Accumulated impairment losses	(14,278)	(14,278)	(14,278)
Goodwill, net	4,878		4,878
Goodwill acquired		$ 4,878
miraDry
Goodwill and intangible assets
Goodwill			7,629
Goodwill, net			$ 7,629
Goodwill acquired	$ 7,629

Goodwill and Intangible Asset51

Goodwill and Intangible Assets - Components of Other Intangible Assets (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016
Other intangible assets
Gross Carrying Amount	$ 23,003	$ 8,203
Accumulated Amortization	(4,650)	(2,467)
Intangible Assets, net	18,353	5,736
Indefinite-lived intangible assets	450	450
Trade name
Other intangible assets
Indefinite-lived intangible assets	$ 450	$ 450
Customer relationships
Other intangible assets
Average Amortization Period (in years)	11 years	10 years
Gross Carrying Amount	$ 11,240	$ 4,940
Accumulated Amortization	(1,859)	(602)
Intangible Assets, net	$ 9,381	$ 4,338
Trade name
Other intangible assets
Average Amortization Period (in years)	14 years	12 years
Gross Carrying Amount	$ 5,800	$ 800
Accumulated Amortization	(216)	(56)
Intangible Assets, net	$ 5,584	$ 744
Developed technology
Other intangible assets
Average Amortization Period (in years)	15 years
Gross Carrying Amount	$ 3,000
Accumulated Amortization	(95)
Intangible Assets, net	$ 2,905
Distributor relationships
Other intangible assets
Average Amortization Period (in years)	9 years
Gross Carrying Amount	$ 500
Accumulated Amortization	(40)
Intangible Assets, net	$ 460
Non-compete agreement
Other intangible assets
Average Amortization Period (in years)	2 years	2 years
Gross Carrying Amount	$ 80	$ 80
Accumulated Amortization	(57)	(17)
Intangible Assets, net	$ 23	$ 63
Regulatory approvals
Other intangible assets
Average Amortization Period (in years)	1 year	1 year
Gross Carrying Amount	$ 670	$ 670
Accumulated Amortization	$ (670)	(96)
Intangible Assets, net		$ 574
Acquired FDA non-gel product approval
Other intangible assets
Average Amortization Period (in years)	11 years	11 years
Gross Carrying Amount	$ 1,713	$ 1,713
Accumulated Amortization	$ (1,713)	(1,696)
Intangible Assets, net		$ 17

Goodwill and Intangible Asset52

Goodwill and Intangible Assets - Schedule of Estimated Amortization Expense (Details) $ in Thousands	Dec. 31, 2017USD ($)
Estimated amortization expense
2,018	$ 2,308
2,019	2,321
2,020	2,209
2,021	1,996
2,022	1,762
Thereafter	7,757
Total amortization	$ 18,353

Income Taxes - Schedule of Prov

Income Taxes - Schedule of Provision for Income Tax (Details) - USD ($)	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Operating loss carryforwards
Income tax (benefit) expense	$ (17,000)	$ 61,000	$ 0
Deferred tax, State	17,000	6,000
Total Deferred tax	(21,000)	61,000	$ 0
Federal
Operating loss carryforwards
Income tax (benefit) expense	$ (38,000)	$ 55,000

Income Taxes (Details)

Income Taxes (Details) - USD ($)	Jan. 02, 2017	Jan. 02, 2016	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Operating loss carryforwards
Current income tax expense related to foreign jurisdictions				$ 4,000
Current income tax (benefit) expense					$ 0	$ 0
Income tax (benefit) expense				(17,000)	61,000	0
Deferred income taxes				$ (21,000)	61,000	0
Statutory federal income tax rate
Statutory federal income tax rate (as a percent)				34.00%
Deferred tax assets:
Valuation allowance against deferred tax assets				$ 71,075,000	80,470,000
Accumulated deficit				(279,470,000)	(215,442,000)
Decrease in deferred tax assets before valuation allowance				34,600,000
Tax Credit Carryforwards
Unrecognized tax benefits				$ 966,000	732,000	$ 732,000
Taxable income for net operating loss carryforwards				80.00%
Unrecognized Tax Benefits Penalties and Interest
Interest expense or penalties related to unrecognized tax benefits				$ 0
Scenario Plan
Statutory federal income tax rate
Statutory federal income tax rate (as a percent)			21.00%
Accounting Standards Update 2016-09
Deferred tax assets:
Cumulative excess benefits related to share based compensation				100,000
Accumulated deficit	$ 0			0
Accounting Standards Update 2016-09 | Deferred Tax Assets And Valuation Allowance
Deferred tax assets:
Increase in deferred tax assets and valuation allowance	$ 100,000	$ 100,000
Research and development
Tax Credit Carryforwards
Tax credit carryforwards				1,900,000	2,100,000
Unrecognized tax benefits				1,000,000
Federal
Operating loss carryforwards
Income tax (benefit) expense				(38,000)	$ 55,000
Deferred tax assets:
Net operating loss carryforwards				$ 239,000,000
Net operating loss carryforwards, expiration year				2,027
State
Deferred tax assets:
Net operating loss carryforwards				$ 138,000,000
Net operating loss carryforwards, expiration year				2,017

Income Taxes - Schedule of Reco

Income Taxes - Schedule of Reconciliation of Actual Income Tax Expense Obtained by Applying Statutory Federal Income Tax Rate (Details) - USD ($)	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Reconciliation of actual income tax expense obtained by applying the statutory federal income tax rate
Tax at federal statutory rate	$ (21,776,000)	$ (13,636,000)	$ (14,018,000)
State, net of federal benefit	(2,637,000)	(1,321,000)	(1,624,000)
Permanent items	1,327,000	1,420,000	898,000
Research and development credits	(53,000)
State rate change	(56,000)	87,000	180,000
Other	(103,000)	9,000	1,000
Change in federal statutory rate	34,555,000
Change in valuation allowance	(11,274,000)	13,502,000	14,563,000
Total	$ (17,000)	$ 61,000	$ 0

Income Taxes - Schedule of Tax

Income Taxes - Schedule of Tax Effects of Temporary Differences and Carryforwards that Give Rise to Significant Portions of Deferred Tax Assets (Details) - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2016
Deferred tax assets:
Net operating loss carryforwards	$ 61,171	$ 65,626
Research and development credits	3,049	2,233
Accruals and reserves	4,993	4,362
Intangibles	5,605	8,309
Gross deferred tax assets	74,818	80,530
Less valuation allowance	(71,075)	(80,470)
Total deferred tax assets	3,743	60
Depreciation	(18)	(60)
Intangibles - deferred tax liability	(3,663)
Indefinite-lived intangibles (naked credit)	(102)	(61)
Total deferred tax liabilities	(3,783)	(121)
Net deferred taxes	$ (40)	$ (61)

Income Taxes - Schedule of Re57

Income Taxes - Schedule of Reconciliation of Beginning and Ending Amount of Unrecognized Tax Benefits (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016
Reconciliation of the beginning and ending amount of unrecognized tax benefits
Balance at beginning of the period	$ 732	$ 732
Additions based on acquisitions during the current year	186
Additions based on tax positions taken in the current year	48	0
Balance at end of the period	$ 966	$ 732

Employee Benefit Plans (Details

Employee Benefit Plans (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016
Compensation And Retirement Disclosure [Abstract]
Company contribution (as a percent)		3.00%
Company contribution	$ 0.6	$ 0.1

Stockholders' Equity (Details)

Stockholders' Equity (Details) - $ / shares	Dec. 31, 2017	Dec. 31, 2016
Stock other disclosures
Common and preferred stock, shares authorized	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)

Stockholders' Equity (Warrants) (Details) - $ / shares	Jan. 17, 2013	Jun. 30, 2014	Dec. 31, 2017
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 loan | 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)

Stockholders' Equity (Options) (Details) - USD ($) $ / shares in Units, $ in Millions	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2017	Nov. 03, 2014	Apr. 30, 2007
Stock options
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Balance at the end of the period (in shares)	2,786,977	2,785,672	2,785,672	2,179,787
Number of options
Balance at the beginning of period (in shares)	2,786,977	2,785,672
Options granted (in shares)	180,000	571,753
Options exercised (in shares)	(480,236)	(478,099)
Options forfeited (in shares)	(306,954)	(92,349)
Balance at the end of the period (in shares)	2,179,787	2,786,977	2,785,672
Number of options vested and expected to vest (in shares)				2,179,787
Number of options vested and exercisable (in shares)				1,336,308
Weighted average exercise price
Balance at the beginning of period (in dollars per share)	$ 7.27	$ 6.66
Options granted (in dollars per share)	9.12	7.08
Options exercised (in dollars per share)	2.80	1.93
Options forfeited (in dollars per share)	13.01	15.35
Balance at the end of period (in dollars per share)	$ 7.60	$ 7.27	$ 6.66
Weighted average exercise price, vested and expected to vest (in dollars per share)				$ 7.60
Weighted average exercise price, vested and exercisable (in dollars per share)				$ 7.85
Additional information
Weighted average remaining contractual term	7 years 3 months 7 days	6 years 3 months 11 days	6 years 7 months 6 days
Weighted average remaining contractual term, vested and exercisable	6 years 7 months 28 days
Weighted average grant date fair value (in dollars per share)	$ 4.54	$ 3.97	$ 4.60
Stock-based compensation expense	$ 2.2	$ 1.7	$ 2
Number of years from the date of grant for tax benefits	2 years
Number of years from the date of exercise for tax benefits	1 year
Unrecognized compensation costs (in dollars)				$ 2.5
Weighted average period over which unrecognized compensation costs are expected to be recognized	1 year 11 months 23 days
Aggregate intrinsic value (in dollars)	$ 3.1	$ 3	$ 0.6
2007 Plan
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Common stock reserved for issuance (in shares)						1,690,448
Balance at the end of the period (in shares)	493,943			493,943
Number of shares available for future grants				0
Number of options
Balance at the end of the period (in shares)	493,943
2014 Plan
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Common stock reserved for issuance (in shares)				2,789,442	1,027,500
Number of shares available for future grants				321,570
Inducement Plan
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Number of shares available for future grants				34,000
Number of shares awarded	330,000
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%
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 (Restricte

Stockholders' Equity (Restricted Stock) (Details) - Restricted stock units - 2014 Plan - USD ($) $ / shares in Units, $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Stockholders' Equity, other disclosures
Requisite service period, quarterly	4 years
Requisite service period, annually	3 years
Granted	$ 9.19	$ 8.21	$ 3.88
Stock-based compensation expense	$ 4,100	$ 1,200	$ 2
Unrecognized compensation costs (in dollars)	$ 5,700
Weighted average period over which unrecognized compensation costs are expected to be recognized	1 year 10 months 20 days
Number of shares
Balance at beginning of the period	430,733	17,993
Granted	832,145	557,240
Vested	(293,910)	(4,500)
Forfeited	(40,416)	(140,000)
Balance at end of the period	928,552	430,733	17,993
Weighted average grant date fair value
Balance at beginning of the period	$ 7.99	$ 3.88
Granted	9.19	8.21	$ 3.88
Vested	7.75	3.88
Forfeited	8.47	8.44
Balance at end of the period	$ 9.12	$ 7.99	$ 3.88

Stockholders' Equity (Stock Pur

Stockholders' Equity (Stock Purchase) (Details) - 2014 Employee Stock Purchase Plan - USD ($) $ / shares in Units, $ in Millions	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015	Oct. 31, 2014
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%
Number of shares reserved for future issuance	770,549
Rate of increase in the number of shares available for grant every year on outstanding common stock (as a percent)	1.00%
Number of shares available for future grants	495,551
Purchases under the award	108,081	122,667
Weighted Average purchase price	$ 5.98	$ 6.14
Stock-based compensation expense	$ 0.4	$ 0.3	$ 0.4
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
Number of shares available for future grants	3,000,000

Segment Reporting and Geograp64

Segment Reporting and Geographic Information (Details)	12 Months Ended
	Dec. 31, 2017USD ($)Segment
Segment Reporting [Abstract]
Number of reportable segments | Segment	2
Segments unallocated expenses | $	$ 0

Segment Reporting and Geograp65

Segment Reporting and Geographic Information - Summary of Net Sales and Net Operating Loss by Reportable Segment (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Segment Reporting Information [Line Items]
Total net sales	$ 36,542	$ 20,734	$ 38,106
Total loss from operations	(62,890)	(40,034)	(38,525)
Breast Product
Segment Reporting Information [Line Items]
Total net sales	31,485	20,734	38,106
Total loss from operations	(56,657)	$ (40,034)	$ (38,525)
miraDry
Segment Reporting Information [Line Items]
Total net sales	5,057
Total loss from operations	$ (6,233)

Segment Reporting and Geograp66

Segment Reporting and Geographic Information - Summary of Net Sales by Geographical Regions (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Segment Reporting Information [Line Items]
Total net sales	$ 36,542	$ 20,734	$ 38,106
North America
Segment Reporting Information [Line Items]
Total net sales	33,473	$ 20,734	$ 38,106
International
Segment Reporting Information [Line Items]
Total net sales	$ 3,069

Commitments and Contingencies67

Commitments and Contingencies (Details)	Sep. 07, 2017USD ($)	Jul. 27, 2017USD ($)USD_Per_Unit	Nov. 19, 2015lawsuit	Mar. 31, 2014USD ($)	Dec. 31, 2013	Aug. 31, 2013	Mar. 31, 2017USD ($)	Dec. 31, 2017USD ($)	Dec. 31, 2016USD ($)	Dec. 31, 2015USD ($)
Loss Contingencies [Line Items]
Lease contract term				68 months	62 months	4 months		1 year
Lease commencement date				Jul. 1, 2014	Mar. 1, 2014	Sep. 1, 2013
Operating lease expiration date						Jan. 31, 2019		Nov. 30, 2018
Rent expense								$ 1,100,000	$ 500,000	$ 500,000
Contingencies
General and administrative								31,537,000	21,959,000	$ 18,738,000
Insurance recovery receivable								39,000	9,375,000
Insurance recovery receivable								9,336,000	(9,375,000)
Legal settlement payable								1,000,000	$ 10,900,000
Litigation settlement agreement, amount paid or to be paid	$ 9,000,000
Royalty payments on each of net sales per product | USD_Per_Unit		12.50
Litigation settlement expense								10,000,000
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
Insurance recovery receivable							$ 9,300,000
Legal settlement payable							$ 10,900,000
Litigation Settlement in 2018
Contingencies
Litigation settlement agreement, amount paid or to be paid		$ 1,000,000
Other Assets
Loss Contingencies [Line Items]
Restricted cash balance				$ 300,000

Commitments and Contingencies -

Commitments and Contingencies - Schedule of Future Minimum Lease Payments under Non-cancelable Operating Leases (Details) $ in Thousands	Dec. 31, 2017USD ($)
Future minimum lease payments
2,018	$ 1,164
2,019	1,034
2,020	172
Total	$ 2,370

Subsequent Events (Details)

Subsequent Events (Details) - USD ($) $ in Thousands	Feb. 20, 2018	Dec. 31, 2015
Subsequent Event [Line Items]
Proceeds from follow-on offering, net of costs		$ 61,397
Stifel, Nicolaus & Company, Incorporated
Subsequent Event [Line Items]
Commission percentage on gross prcoeeds	3.00%
Stifel, Nicolaus & Company, Incorporated | Maximum
Subsequent Event [Line Items]
Proceeds from follow-on offering, net of costs	$ 50,000

Summary of Quarterly Financia70

Summary of Quarterly Financial Information (Unaudited) (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2016	Sep. 30, 2016	Jun. 30, 2016	Mar. 31, 2016	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Selected Quarterly Financial Information [Abstract]
Net sales	$ 11,065	$ 9,819	$ 8,169	$ 7,489	$ 6,488	$ 6,531	$ 6,244	$ 1,471	$ 36,542	$ 20,734	$ 38,106
Gross profit	5,321	6,335	5,548	5,167	3,927	4,717	4,499	711	22,371	13,854	27,452
Net loss	$ (17,834)	$ (14,381)	$ (20,391)	$ (11,422)	$ (8,073)	$ (9,963)	$ (10,193)	$ (11,937)	$ (64,028)	$ (40,166)	$ (41,230)
Net loss per share:
Basic and diluted	$ (0.92)	$ (0.74)	$ (1.07)	$ (0.61)	$ (0.43)	$ (0.55)	$ (0.56)	$ (0.66)	$ (3.34)	$ (2.20)	$ (2.61)

Schedule II - Valuation And Q71

Schedule II - Valuation And Qualifying Accounts (Details) - Allowance for sales returns - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Valuation And Qualifying Accounts [Abstract]
Balance at beginning of period	$ 3,908	$ 660	$ 10,018
Additions charged to costs and expenses	48,098	33,797	85,429
Deductions	(48,100)	(30,549)	(94,787)
Balance at end of period	$ 3,906	$ 3,908	$ 660