Conformis (CFMS) 10-K 8 Mar 17 2016 FY Annual report Financial data

Document and Entity Information

Document and Entity Information - USD ($)	12 Months Ended
	Dec. 31, 2016	Feb. 28, 2017	Jun. 30, 2016
Document and Entity Information
Entity Registrant Name	CONFORMIS INC
Entity Central Index Key	1,305,773
Document Type	10-K
Document Period End Date	Dec. 31, 2016
Amendment Flag	false
Current Fiscal Year End Date	--12-31
Entity Current Reporting Status	Yes
Entity Filer Category	Accelerated Filer
Entity Common Stock, Shares Outstanding		43,820,140
Entity Well-known Seasoned Issuer	No
Entity Voluntary Filers	No
Document Fiscal Year Focus	2,016
Document Fiscal Period Focus	FY
Entity Public Float			$ 153,555,964

Consolidated Balance Sheets

Consolidated Balance Sheets - USD ($) $ in Thousands	Dec. 31, 2016	Dec. 31, 2015
Current Assets
Cash and cash equivalents	$ 37,257	$ 117,185
Investments	28,242	0
Accounts receivable, net	14,675	14,867
Inventories	11,720	11,520
Prepaid expenses and other current assets	3,954	2,451
Total current assets	95,848	146,023
Property and equipment, net	15,084	10,966
Other Assets
Restricted cash	300	600
Intangible assets, net	746	995
Goodwill	753	753
Other long-term assets	79	32
Total assets	112,810	159,369
Current liabilities
Accounts payable	5,474	4,718
Accrued expenses	8,492	7,811
Deferred revenue	305	305
Current portion of long-term debt	0	295
Total current liabilities	14,271	13,129
Other long-term liabilities	164	220
Deferred revenue	4,320	4,625
Long-term debt	0	183
Total liabilities	18,755	18,157
Commitments and contingencies	0	0
Stockholders' equity
Preferred stock, $0.00001 par value:	0	0
Common stock, $0.00001 par value:	0	0
Additional paid-in capital	476,486	467,075
Accumulated deficit	(382,930)	(325,342)
Accumulated other comprehensive income (loss)	499	(521)
Total stockholders’ equity	94,055	141,212
Total liabilities and stockholders’ equity	$ 112,810	$ 159,369

Consolidated Balance Sheets (Pa

Consolidated Balance Sheets (Parenthetical) - $ / shares	Dec. 31, 2016	Dec. 31, 2015
Statement of Financial Position [Abstract]
Preferred stock, par value (in dollars per share)	$ 0.00001	$ 0.00001
Preferred stock, shares authorized	5,000,000	5,000,000
Preferred stock, shares issued	0	0
Preferred stock, shares outstanding	0	0
Common stock, par value (in dollars per share)	$ 0.00001	$ 0.00001
Common stock, shares authorized	200,000,000	200,000,000
Common stock, shares issued	43,399,547	41,110,127
Common stock, shares outstanding	43,399,547	41,110,127

Consolidated Statements of Oper

Consolidated Statements of Operations - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Revenue
Product	$ 78,921	$ 62,791	$ 48,186
Royalty	978	4,096	0
Total revenue	79,899	66,887	48,186
Cost of revenue	53,192	45,102	32,374
Gross profit	26,707	21,785	15,812
Operating expenses
Sales and marketing	41,086	37,558	29,367
Research and development	16,608	16,997	15,107
General and administrative	25,157	23,191	16,763
Total operating expenses	82,851	77,746	61,237
Loss from operations	(56,144)	(55,961)	(45,425)
Other income and expenses
Interest income	487	138	104
Interest expense	(138)	(1,385)	(360)
Loss on extinguishment of debt	0	(205)	0
Foreign currency transaction loss	(1,607)	0	0
Other income (expense)	(123)	208	0
Total other income/(expenses), net	(1,381)	(1,244)	(256)
Loss before income taxes	(57,525)	(57,205)	(45,681)
Income tax provision	63	41	41
Net loss	$ (57,588)	$ (57,246)	$ (45,722)
Net loss per share - basic and diluted	$ (1.39)	$ (2.60)	$ (10.78)
Weighted average common shares outstanding - basic and diluted	41,521,629	21,993,066	4,239,564

Consolidated Statements of Comp

Consolidated Statements of Comprehensive Loss - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Statement of Comprehensive Income [Abstract]
Net loss	$ (57,588)	$ (57,246)	$ (45,722)
Other comprehensive income (loss)
Foreign currency translation adjustments	1,027	(24)	(613)
Change in unrealized gain (loss) on available-for-sale securities, net of tax	(7)	0	0
Comprehensive loss	$ (56,568)	$ (57,270)	$ (46,335)

Consolidated Statements of Chan

Consolidated Statements of Changes in Stockholder's Equity - USD ($) $ in Thousands	Total	Common Stock	Series D convertible preferred stock	Series E-1 convertible preferred stock	Series E-2 convertible preferred stock	Series E-1 and E-2 preferred stock warrants	Common Stock Warrant	Preferred StockConvertible Preferred Stock	Preferred StockSeries D convertible preferred stock	Preferred StockSeries E-1 convertible preferred stock	Preferred StockSeries E-2 convertible preferred stock	Common Stock	Additional Paid-in Capital	Additional Paid-in CapitalCommon Stock	Additional Paid-in CapitalSeries D convertible preferred stock	Additional Paid-in CapitalSeries E-1 convertible preferred stock	Additional Paid-in CapitalSeries E-2 convertible preferred stock	Additional Paid-in CapitalSeries E-1 and E-2 preferred stock warrants	Additional Paid-in CapitalCommon Stock Warrant	Retained Earnings	Accumulated other comprehensive income (loss)	Restricted stock awardsCommon Stock
Beginning balance at Dec. 31, 2013	$ 68,960							$ 0				$ 0	$ 291,218							$ (222,374)	$ 116
Preferred stock, shares outstanding, beginning balance (in shares) at Dec. 31, 2013								47,811,716
Common stock, shares outstanding, beginning balance (in shares) at Dec. 31, 2013												4,161,178
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Issuance of common stock, exercised options (in shares)												124,986
Adjustments to additional paid in capital, share-based compensation, stock options	121												121
Stock issued during period, shares, new issues (in shares)										2,806,480
Stock issued during period, value, new issues	22,452												22,452
Warrants issued	177					$ 42												$ 42
Stock issued during period, shares, warrants exercised									367,456
Stock issued during period, value, warrants exercised	2,205												2,205
Stock-based compensation expense	2,550			$ 302			$ 134						2,550			$ 302			$ 134
Net loss	(45,722)																			(45,722)
Foreign currency translation adjustments	(613)
Ending balance at Dec. 31, 2014	49,827							$ 0				$ 0	318,420							(268,096)	(497)
Preferred stock, shares outstanding, ending balance (in shares) at Dec. 31, 2014								50,985,652
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Change in period	$ (613)																				(613)
Common stock, shares outstanding, ending balance (in shares) at Dec. 31, 2014	4,286,164											4,286,164
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Issuance of common stock, exercised options (in shares)												383,458
Adjustments to additional paid in capital, share-based compensation, stock options	$ 806												806
Stock issued during period, shares, new issues (in shares)	10,350,000											10,350,000										174,530
Stock issued during period, value, new issues	$ 139,766												139,766
Warrants issued	$ 0
Stock issued during period, shares, warrants exercised									321,854	300,059	200,996	11,734
Stock issued during period, value, warrants exercised		$ 18	$ 450	$ 2,400	$ 1,608									$ 18	$ 450	$ 2,400	$ 1,608
Issuance of common stock - preferred stock conversion to common stock	(25,904,241)							(51,808,561)				(25,904,241)
Stock-based compensation expense	$ 3,607												3,607
Net loss	(57,246)																			(57,246)
Foreign currency translation adjustments	(24)
Ending balance at Dec. 31, 2015	$ 141,212							$ 0				$ 0	467,075							(325,342)	(521)
Preferred stock, shares outstanding, ending balance (in shares) at Dec. 31, 2015	0							0
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Change in period	$ (24)																				(24)
Common stock, shares outstanding, ending balance (in shares) at Dec. 31, 2015	41,110,127											41,110,127
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Issuance of common stock, exercised options (in shares)												1,467,692
Adjustments to additional paid in capital, share-based compensation, stock options	$ 4,087												4,087
Stock issued during period, shares, new issues (in shares)																						804,019
Warrants issued	$ 0
Stock issued during period, shares, warrants exercised												17,709
Issuance of common stock - preferred stock conversion to common stock	(25,904,241)
Stock-based compensation expense	$ 5,324												5,324
Net loss	(57,588)																			(57,588)
Foreign currency translation adjustments	1,027
Ending balance at Dec. 31, 2016	$ 94,055							$ 0				$ 0	$ 476,486							$ (382,930)	499
Preferred stock, shares outstanding, ending balance (in shares) at Dec. 31, 2016	0							0
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Change in period	$ 1,020																				$ 1,020
Common stock, shares outstanding, ending balance (in shares) at Dec. 31, 2016	43,399,547											43,399,547

Consolidated Statements of Cash

Consolidated Statements of Cash Flows - USD ($)	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Cash flows from operating activities
Net loss	$ (57,588,000)	$ (57,246,000)	$ (45,722,000)
Adjustments to reconcile net loss to net cash used by operating activities:
Depreciation and amortization expense	3,153,000	2,619,000	2,080,000
Amortization of debt discount	7,000	135,000	24,000
Stock-based compensation expense	5,324,000	3,607,000	2,550,000
Provision for bad debts on trade receivables	188,000	359,000	6,000
Impairment of long term assets	123,000	0	0
Disposal of long term assets	16,000	2,000	44,000
Loss on extinguishment of debt	0	205,000	0
Amortization/accretion on investments	315,000
Changes in operating assets and liabilities:
Accounts receivable	4,000	(6,107,000)	(2,929,000)
Inventories	(200,000)	(3,829,000)	(1,071,000)
Prepaid expenses and other assets	(1,550,000)	(1,045,000)	(332,000)
Accounts payable and accrued liabilities	1,437,000	1,969,000	2,075,000
Deferred royalty revenue	(305,000)	4,932,000	0
Other long-term liabilities	(56,000)	(51,000)	(264,000)
Net cash used in operating activities	(49,132,000)	(54,450,000)	(43,539,000)
Cash flows from investing activities:
Acquisition of property and equipment	(7,161,000)	(4,643,000)	(2,614,000)
Decrease in restricted cash	300,000	3,837,000	1,108,000
Purchase of investments	(65,614,000)	0	0
Maturity of investments	37,050,000	0	0
Net cash used in investing activities	(35,425,000)	(806,000)	(1,506,000)
Cash flows from financing activities:
Net proceeds from issuance of preferred stock	0	0	21,598,000
Proceeds from exercise of common stock options	4,087,000	806,000	121,000
Proceeds from exercise of common stock warrant	0	18,000	0
Proceeds from exercise of preferred stock warrant	0	4,458,000	0
Proceeds from issuance of debt	0	0	10,000,000
Payments on notes payable	(485,000)	(10,278,000)	(2,382,000)
Payment on extinguishment of debt	0	(205,000)	0
Net proceeds from issuance of common stock	0	139,766,000	0
Net cash provided by financing activities	3,602,000	134,565,000	29,337,000
Foreign exchange effect on cash and cash equivalents	1,027,000	(24,000)	(613,000)
(Decrease) increase in cash and cash equivalents	(79,928,000)	79,285,000	(16,321,000)
Cash and cash equivalents, beginning of period	117,185,000	37,900,000	54,221,000
Cash and cash equivalents, end of period	37,257,000	117,185,000	37,900,000
Supplemental information:
Cash paid for income taxes	52,000	187,000	156,000
Cash paid for interest	48,000	1,284,000	162,000
Noncash investing and financing activities
Issuances of Series E-1 preferred stock warrants	$ 0	$ 0	$ 177,000

Organization and Basis of Prese

Organization and Basis of Presentation	12 Months Ended
	Dec. 31, 2016
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Organization and Basis of Presentation	Organization and Basis of Presentation ConforMIS, Inc. and subsidiaries (the “Company”) is a medical technology company that uses its proprietary iFit Image-to-Implant technology platform to develop, manufacture and sell joint replacement implants that are individually sized and shaped, which the Company refers to as customized, to fit each patient’s unique anatomy. The Company’s proprietary iFit® technology platform is potentially applicable to all major joints. The Company offers a broad line of customized knee implants designed to restore the natural shape of a patient’s knee. The Company was incorporated in Delaware and commenced operations in 2004. The Company introduced its iUni and iDuo in 2007, its iTotal CR in 2011 and its iTotal PS in 2015. The Company has its corporate offices in Bedford, Massachusetts. Liquidity and operations Since the Company’s inception in June 2004, it has financed its operations through private placements of preferred stock, its initial public offering in July 2015, bank debt and convertible debt financings, equipment purchase loans, and, beginning in 2007, product revenue. The Company’s product revenue has continued to grow from year-to-year; however, it has not yet attained profitability and continues to incur operating losses. At December 31, 2016 , the Company had an accumulated deficit of $382.9 million . The Company anticipates that its principal sources of funds in the future will be revenue generated from the sales of its products, borrowings under our 2017 Secured Loan Agreement, future capital raises through the issuance of equity securities, and revenues that may be generated in connection with licensing its intellectual property. At December 31, 2016 , the Company had cash and cash equivalents and investments of $65.5 million and $0.3 million in restricted cash allocated to a lease deposit. At December 31, 2015 , the Company had cash and cash equivalents and investments of $117.2 million and $0.6 million in restricted cash allocated to lease deposits. In January 2017, the Company entered into the 2017 Secured Loan Agreement with Oxford consisting of three term loans issued by Oxford with $15 million issued for each of the first two term loans and $20 million issued for the third term loan, in each case, subject to the satisfaction of certain revenue milestones and customary drawdown conditions. In January 2017, in connection with the entry into the 2017 Secured Loan Agreement, the Company drew down the first $15 million term loan. For further information regarding this facility, see “Note R—Subsequent Events—2017 Secured Loan Agreement” in the financial statements and related notes appearing elsewhere in this Annual Report on Form 10-K. Additionally, in January 2017, the Company filed a shelf registration statement on Form S-3 with the SEC. Upon being declared effective by the SEC, the shelf registration statement will allow the Company to sell from time to time up to $200 million of common stock, preferred stock, debt securities, warrants, or units comprised of any combination of these securities, for its own account in one or more offerings. The shelf registration statement, once effective, is intended to provide the Company flexibility to conduct sales of our registered securities, subject to market conditions and our future capital needs. The terms of any offering under the shelf registration statement will be established at the time of such offering and will be described in a prospectus supplement filed with the SEC prior to the completion of any such offering. For further information regarding this shelf registration, see “Note R—Subsequent Events—S-3 Shelf Registration” in the financial statements and related notes appearing elsewhere in this Annual Report on Form 10-K. At December 31, 2016 , the Company had cash and cash equivalents and investments of $65.5 million and $0.3 million in restricted cash allocated to lease deposits. Based on its current operating plan, the Company expects that its existing cash and cash equivalents as of December 31, 2016 , borrowings under its 2017 Secured Loan Agreement, and anticipated revenue from operations, including from projected sales of its products, will enable it to fund its operating expenses and capital expenditure requirements and pay its debt service as it becomes due for at least the next 12 months from the date of filing. The Company has based this expectation on assumptions that may prove to be wrong, such as the revenue that it expects to generate from the sale of its products and the gross profit the Company expects to generate from those revenues, and it could use its capital resources sooner than we expect. In the event the Company’s operating plan is not sufficient to fund its operations, the Company may need to engage in equity or debt financings to secure additional funds. The Company may not be able to obtain additional financing on terms favorable to the Company, or at all. Basis of presentation and use of estimates The preparation of consolidated financial statements in conformity with accounting principles generally accepted in the United States requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities and disclosure of contingent assets and liabilities at the date of the consolidated financial statements, and the reported amounts of revenue and expenses during the reporting periods. The most significant estimates used in these consolidated financial statements include the valuation of accounts receivable, inventory reserves, intangible valuation, equity instruments, impairment assessments, income tax reserves and related allowances, and the lives of property and equipment. Actual results may differ from those estimates.

Summary of Significant Accounti

Summary of Significant Accounting Policies	12 Months Ended
	Dec. 31, 2016
Accounting Policies [Abstract]
Summary of Significant Accounting Policies	Summary of Significant Accounting Policies Concentrations of credit risk and other risks and uncertainties Financial instruments that subject the Company to credit risk primarily consist of cash, cash equivalents and accounts receivable. The Company maintains the majority of its cash with accredited financial institutions. The Company and its contract manufacturers rely on sole source suppliers and service providers for certain components. There can be no assurance that a shortage or stoppage of shipments of the materials or components that the Company purchases will not result in a delay in production or adversely affect the Company’s business. The Company is in the process of validating alternate suppliers relative to certain key components, which are expected to be phased in during the coming periods. For the years ended December 31, 2016 , 2015 and 2014 , no customer represented greater than 10% of revenue. There were no customers that represented greater than 10% of total gross receivable balance at December 31, 2016 , 2015 and 2014 . Principles of consolidation The consolidated financial statements include the accounts of the Company and its wholly owned subsidiaries including ImaTx, Inc., ConforMIS Europe GmbH, ConforMIS UK Limited and ConforMIS Hong Kong Limited. All material intercompany balances and transactions have been eliminated in consolidation. Cash and cash equivalents The Company considers all highly liquid investment instruments with original maturities of 90 days or less when purchased, to be cash equivalents. The Company’s cash equivalents consist of demand deposits and money market accounts on deposit with certain financial institutions in excess of federally insured limits. Demand deposits are carried at cost which approximates their fair value. Money market accounts are carried at fair value based upon level 1 inputs. See “Note C — Fair Value Measurements” below. The associated risk of concentration is mitigated by banking with credit worthy financial institutions. The Company had $1.6 million as of December 31, 2016 and $2.1 million as of December 31, 2015 held in foreign bank accounts, that was not federally insured. In addition, the Company has recorded restricted cash of $0.3 million as of December 31, 2016 and $0.6 million as of December 31, 2015 of security provided for a lease obligation. Investment securities The Company classifies its investment securities as available-for-sale. Those investments with maturities less than 12 months at the date of purchase are considered short-term investments. Those investments with maturities greater than 12 months at the date of purchase are considered long-term investments. The Company’s investment securities classified as available-for-sale are recorded at fair value based upon quoted market prices at period end. Unrealized gains and losses, deemed temporary in nature, are reported as a separate component of accumulated other comprehensive income (loss). A decline in the fair value of any security below cost that is deemed other than temporary results in a charge to earnings and the corresponding establishment of a new cost basis for the security. Premiums (discounts) are amortized (accreted) over the life of the related security the constant yield method. Dividend and interest income are recognized when earned and reported in other income. Realized gains and losses are included in earnings and are derived using the specific identification method for determining the cost of securities sold. Fair value of financial instruments Certain of the Company’s financial instruments, including cash and cash equivalents, excluding money market funds, accounts receivable, accounts payable, accrued expenses and other liabilities are carried at cost, which approximates their fair value because of the short-term maturity. Based on borrowing rates currently available to the Company for loans with similar terms, the carrying value of the Company’s long-term debt approximates its fair value. Accounts receivable and allowance for doubtful accounts Accounts receivable consist of amounts due from medical facilities that have been billed and unbilled. Upon completion of a procedure, revenue is recognized and unbilled receivable is recorded. Upon receipt of a purchase order number from the medical facility, which is used by the medical facility to facilitate payment, a billed receivable is recorded and the unbilled receivable is reversed. The unbilled receivable balance fluctuates based on the timing of when purchase order numbers are received from medical facilities. In estimating whether accounts receivable can be collected, the Company performs evaluations of customers and continuously monitors collections and payments and estimates an allowance for doubtful accounts based on the aging of the underlying invoices, collections experience to date and any specific collection issues that have been identified. The allowance for doubtful accounts is recorded in the period in which revenue is recorded or when collection risk is identified. Inventories Inventories consist of raw materials, work-in-process components and finished goods. Inventories are stated at the lower of cost, determined using the first-in first-out method, or market value. The Company regularly reviews its inventory quantities on hand and related cost and records a provision for any excess or obsolete inventory based on its estimated forecast of product demand and existing product configurations. The Company also reviews its inventory value to determine if it reflects the lower of cost or market, with market determined based on net realizable value. Appropriate consideration is given to inventory items sold at negative gross margins, purchase commitments and other factors in evaluating net realizable value. During the years ended December 31, 2016 , 2015 and 2014 , the Company recognized provisions of $3.5 million , $2.7 million and $1.7 million , respectively, to adjust its inventory value to the lower of cost or market for estimated unused product related to known and potential cancelled cases, which is included in cost of revenue. Property and equipment Property and equipment is stated at cost less accumulated depreciation and is depreciated using the straight-line method over the estimated useful lives of the respective assets. Leasehold improvements are amortized over their useful life or the life of the lease, whichever is shorter. Assets capitalized under capital leases are amortized in accordance with the respective class of assets and the amortization is included with depreciation expense. Maintenance and repair costs are expensed as incurred. Intangibles and other long-lived assets Intangible assets consist of developed technology and other intellectual property rights licensed from ImaTx as part of the spin-out transaction in 2004. Intangible assets are carried at cost less accumulated amortization. The Company tests impairment of long-lived assets when events or changes in circumstances indicate that the assets might be impaired. For assets with determinable useful lives, amortization is computed using the straight-line method over the estimated economic lives of the respective intangible assets. Furthermore, periodically the Company assesses whether long-lived assets, including intangible assets, should be tested for recoverability whenever events or circumstances indicate that their carrying value may not be recoverable. The amount of impairment, if any, is measured based on fair value, which is determined using estimated undiscounted cash flows to be generated from such assets or group of assets. If the cash flow estimates or the significant operating assumptions upon which they are based change in the future, the Company may be required to record impairment charges. During the year ended December 31, 2016 , the Company recognized an impairment of long-term assets of $0.1 million in connection with certain manufacturing equipment previously purchased that was returned to the seller in exchange for credit toward future purchase. The value of such credit is less than the book value of the equipment. During the years ended December 31, 2015 and 2014 , no such impairment charges were recognized. Goodwill Goodwill relates to amounts that arose in connection with the acquisition of Imaging Therapeutics, Inc. (formerly known as Osteonet.com, renamed ImaTx, Inc.) in 2009. The Company tests goodwill at least annually for impairment, or more frequently when events or changes in circumstances indicate that the assets may be impaired. This impairment test is performed annually during the fourth quarter at the reporting unit level. Goodwill may be considered impaired if the carrying value of the reporting unit, including goodwill, exceeds the reporting unit’s fair value. The Company is comprised of one reporting unit. When testing goodwill for impairment, the Company has the option to first assess the qualitative factors to determine whether it is more likely than not that the fair value of its reporting unit is less than its carrying amount. This qualitative analysis is used as a basis for determining whether it is necessary to perform the two-step goodwill impairment analysis. If the Company determines that it is more likely than not that its fair value is less than its carrying amount, then the two-step goodwill impairment test will be performed. If the two-step approach is performed, the Company will estimate fair value of the reporting unit, which is typically estimated using a discounted cash flow approach, and requires the use of assumptions and judgments including estimates of future cash flows and the selection of discount rates. During the years ended December 31, 2016 , 2015 and 2014 , there were no triggering events which would require the two-step goodwill impairment assessment. Revenue recognition Product The Company generates revenue from the sale of customized implants and instruments to medical facilities through the use of a combination of direct sales personnel, independent sales representatives and distributors in the United States, Germany, the United Kingdom, Ireland, Austria, Switzerland, Singapore and Hong Kong. Revenue is recognized when all of the following criteria are met: • persuasive evidence of an arrangement exists; • the sales price is fixed or determinable; • collection of the relevant receivable is probable at the time of sale; and • delivery has occurred or services have been rendered. For a majority of sales to medical facilities, the Company recognizes revenue upon completion of the procedure, which represents satisfaction of the required revenue recognition criteria. For the remaining sales, which are made directly through distributors and generally represent approximately 1% of revenue, the Company recognizes revenue at the time of shipment of the product, which represents the point in time when the customer has taken ownership and assumed the risk of loss and the required revenue recognition criteria are satisfied. Such customers are obligated to pay within specified time periods regardless of when or if they ever sell or use the products. Once the revenue recognition criteria have been satisfied the Company does not offer rights of return or price protection and there are no post-delivery obligations. Royalty In April 2015, the Company entered into a fully paid up, worldwide license agreement with Wright Medical Group, Inc., or Wright Group, and its wholly owned subsidiary Wright Medical Technology, Inc., or Wright Technology and collectively with Wright Group, Wright Medical. Under the terms of this license agreement, the Company granted a perpetual, irrevocable, non-exclusive license to Wright Medical to use patient-specific instrument technology covered by the Company’s patents and patent applications with off-the-shelf implants in the foot and ankle. This license does not extend to patient-specific implants. This license agreement provided for a single lump-sum payment by Wright Medical to the Company upon entering into the license agreement, which has been paid. This license agreement will expire upon the expiration of the last to expire of the Company’s patents and patent applications licensed to Wright Medical, which currently is expected to occur in 2031. In April 2015, the Company entered into a worldwide license agreement with MicroPort Orthopedics Inc., or MicroPort, a wholly owned subsidiary of MicroPort Scientific Corporation. Under the terms of this license agreement, the Company granted a perpetual, irrevocable, non-exclusive license to MicroPort to use patient-specific instrument technology covered by the Company’s patents and patent applications with off-the-shelf implants in the knee. This license does not extend to patient-specific implants. This license agreement provides for the payment to the Company of a fixed royalty percentage of net sales on patient-specific instruments and associated implant components in the knee, including MicroPort’s Prophecy patient-specific instruments used with its Advance and Evolution implant components. This license agreement also provided for a single lump-sum payment by MicroPort to the Company upon entering into the license agreement, which has been paid. This license agreement will expire upon the expiration of the last to expire of the Company’s patents and patent applications licensed to MicroPort, which currently is expected to occur in 2029. The Company has accounted for the agreements with Wright Medical and MicroPort under ASC 605-25, Multiple-Element Arrangements and Staff Accounting Bulletin No. 104, Revenue Recognition (ASC 605). In accordance with ASC 605, the Company is required to identify and account for each of the separate units of accounting. The Company identified the relative selling price for each and then allocated the total consideration based on their relative values. In connection with these agreements, in April 2015, the Company recognized in aggregate (i) back-owed royalties of $3.4 million as royalty revenue and (ii) the value attributable to the settlements of $0.2 million as other income. Additionally, the Company recognized an initial $5.1 million in aggregate as deferred royalty revenue, which is recognized as royalty revenue ratably through 2031. See “Note I — Deferred Revenue”. The on-going royalty from MicroPort is recognized as royalty revenue upon receipt of payment. Shipping and handling costs Amounts invoiced to customers for shipping and handling are classified as revenue. Shipping and handling costs incurred are included in general and administrative expense. Shipping and handling expense was $1.6 million , $2.7 million and $1.4 million for the years ended December 31, 2016 , 2015 and 2014 , respectively. Taxes collected from customers and remitted to government authorities The Company’s policy is to present taxes collected from customers and remitted to government authorities on a net basis and not to include tax amounts in revenue. Research and development expense The Company’s research and development costs consist of engineering, product development, quality assurance, clinical and regulatory expense. These costs primarily relate to employee compensation, including salary, benefits and stock-based compensation. The Company also incurs costs related to consulting fees, materials and supplies, and marketing studies, including data management and associated travel expense. Research and development costs are expensed as incurred. Advertising expense Advertising costs are expensed as incurred, which are included in sales and marketing. Advertising expense was $0.3 million for the year ended December 31, 2016 , $0.3 million for the year ended December 31, 2015 and $0.5 million for the year ended December 31, 2014 . Segment reporting Operating segments are defined as components of an enterprise about which separate financial information is available and is evaluated on a regular basis by the chief operating decision-maker, or decision-making group, in deciding how to allocate resources to an individual segment and in assessing performance of the segment. The Company’s chief operating decision-maker is its chief executive officer. The Company’s chief executive officer reviews financial information presented on an aggregate basis for purposes of allocating resources and evaluating financial performance. The Company has one business activity and there are no segment managers who are held accountable for operations, operating results and plans for products or components below the aggregate Company level. Accordingly, in light of the Company’s current product offerings, management has determined that the primary form of internal reporting is aligned with the offering of the ConforMIS customized joint replacement products and that the Company operates as one segment. See “Note O——Segment and Geographic Data”. Comprehensive loss At December 31, 2016 , 2015 and 2014 , accumulated other comprehensive loss consists of foreign currency translation adjustments and changes in unrealized gain and loss of available-for-sale securities, net of tax. The following table summarizes accumulated beginning and ending balances for each item in Accumulated other comprehensive income (loss). Foreign currency translation adjustments Change in unrealized gain (loss) on available-for-sale securities, net of tax Accumulated other comprehensive income (loss) Balance December 31, 2015 $ (521 ) $ — $ (521 ) Change in period 1,027 (7 ) 1,020 Balance December 31, 2016 $ 506 $ (7 ) $ 499 Foreign currency translation and transactions The assets and liabilities of the Company’s foreign operations are translated into U.S. dollars at current exchange rates at the balance sheet date, and income and expense items are translated at average rates of exchange prevailing during the year. Gains and losses realized from transactions denominated in foreign currencies, including intercompany balances not considered permanent investments, are included in the consolidated statements of operations. Income taxes Income taxes are accounted for under the asset and liability method. Deferred tax assets and liabilities are recognized for the future tax consequences attributable to differences between the consolidated financial statement carrying amounts of existing assets and liabilities and their respective tax bases, operating losses and tax credit carry forwards. Deferred tax assets and liabilities are measured using enacted tax rates expected to apply to taxable income in the years in which those temporary differences are expected to be recovered or settled. The effect on deferred tax assets and liabilities of a change in tax rates is recognized as income in the period that includes the enactment date. The tax benefit from an uncertain tax position is only recognized if it is more likely than not that the tax position will be sustained on examination by the taxing authorities, based on the technical merits of the position. The tax benefits recognized in the consolidated financial statements from these positions are measured based on the largest benefit that has a greater than fifty percent likelihood of being realized upon ultimate resolution. The Company reviews its tax positions on an annual basis and more frequently as facts surrounding tax positions change. Based on these future events, the Company may recognize uncertain tax positions or reverse current uncertain tax positions, the impact of which would affect the consolidated financial statements. Medical device excise tax The Company is subject to the Health Care and Education Reconciliation Act of 2010 (the “Act”), which imposes a tax equal to 2.3% on the sales price of any taxable medical device by a medical device manufacturer, producer or importer of such device. Under the Act, a taxable medical device is any device defined in section 201(h) of the Federal Food, Drug, and Cosmetic Act, intended for humans, which includes an instrument, apparatus, implement, machine, contrivance, implant, in vitro reagent, or other similar or related article, including any component, part, or accessory, which meets certain requirements. The Consolidated Appropriations Act of 2016 includes a two-year moratorium on the medical device excise tax, which moratorium suspended taxes on the sale of a taxable medical device by the manufacturer, producer, or importer of the device during the period beginning on January 1, 2016 and ending on December 31, 2017. As such, the Company did not incur medical device excise tax expense for the year ended December 31, 2016 . The Company incurred medical device excise tax expense of $0.8 million for the year ended December 31, 2015 and $0.7 million for the year ended December 31, 2014 , respectively. Medical device tax is included in general and administrative expense. Stock-based compensation The Company accounts for stock-based compensation in accordance with ASC 718, Stock Based Compensation. ASC 718 requires all stock-based payments to employees and consultants, including grants of stock options, to be recognized in the consolidated statements of operations based on their fair values. The Company uses the Black-Scholes option pricing model to determine the weighted-average fair value of options granted and recognizes the compensation expense of stock-based awards on a straight-line basis over the vesting period of the award. The determination of the fair value of stock-based payment awards utilizing the Black-Scholes option pricing model is affected by the stock price, exercise price, and a number of assumptions, including expected volatility of the stock, expected life of the option, risk-free interest rate and expected dividends on the stock. The Company evaluates the assumptions used to value the awards at each grant date and if factors change and different assumptions are utilized, stock-based compensation expense may differ significantly from what has been recorded in the past. If there are any modifications or cancellations of the underlying unvested securities, the Company may be required to accelerate, increase or cancel any remaining unearned stock-based compensation expense. The stock price for option grants are set by the Company’s board of directors and, prior to the Company’s IPO in July 2015, were based upon guidance set forth by the American Institute of Certified Public Accountants, or AICPA, in its Technical Practice Aid, “Valuation of Privately Held Company Equity Securities Issued as Compensation”. To that end, the board considered a number of factors in determining the option price, including: (1) past sales of the Company’s convertible preferred stock, and the rights, preferences and privileges of the Company stock, (2) obtaining FDA 510(k) clearance, and (3) achievement of budgeted results. See “Note M——Stockholders’ Equity” for a summary of the stock option activity under the Company’s stock-based compensation plan. Net loss per share The Company calculates net loss per share in accordance with Accounting Standards Codification 260, Earnings per Share. Basic earnings per share (“EPS”) is calculated by dividing the net income or loss for the period by the weighted average number of common shares outstanding for the period, without consideration for common stock equivalents. Diluted EPS is computed by dividing the net income or loss for the period by the weighted average number of common shares outstanding for the period and the weighted average number of dilutive common stock equivalents outstanding for the period determined using the treasury stock method. The following table sets forth the computation of basic and diluted earnings per share attributable to stockholders (in thousands, except share and per share data): Years Ended December 31, (in thousands, except share and per share data) 2016 2015 2014 Numerator: Numerator for basic and diluted loss per share: Net loss $ (57,588 ) $ (57,246 ) $ (45,722 ) Denominator: Denominator for basic loss per share: Weighted average shares 41,521,629 21,993,066 4,239,564 Basic loss per share attributable to ConforMIS, Inc. stockholders $ (1.39 ) $ (2.60 ) $ (10.78 ) Diluted loss per share attributable to ConforMIS, Inc. stockholders $ (1.39 ) $ (2.60 ) $ (10.78 ) The following table sets forth potential shares of common stock equivalents that are not included in the calculation of diluted net loss per share because to do so would be anti-dilutive as of the end of each period presented: Years Ended December 31, 2016 2015 2014 Series A Preferred — 873,591 1,705,138 Series B Preferred — 1,144,885 2,234,668 Series C Preferred — 1,256,752 2,453,018 Series D Preferred — 3,410,570 6,415,106 Series E-1 Preferred — 3,748,578 6,530,429 Series E-2 Preferred — 2,628,037 5,129,592 Series C Preferred Warrants — — 56,202 Series D Preferred Warrants — — 58,365 Series E-2 Preferred Warrants — — 5,883 Common stock warrants 34,709 303,931 25,733 Stock options 1,959,030 3,566,421 2,780,631 Total 1,993,739 16,932,765 27,394,765 Recent accounting pronouncements In November 2016, the Financial Accounting Standards Board ("FASB") issued Accounting Standard Update ("ASU') No. 2016-18, “Statement of Cash Flows (Topic 230) Restricted Cash a consensus of the FASB Emerging Issues Task Force” (“ASU 2016-18”). The standard requires restricted cash and cash equivalents to be included with cash and cash equivalents on the statement cash flows. The guidance will be effective in the first quarter of 2018, with early adoption permitted. The Company is currently evaluating the impact of this pronouncement on its consolidated financial statements and expects to adopt this pronouncement commencing in the first quarter of 2018. In June 2016, the FASB issued ASU No. 2016-12, "Revenue from Contracts with Customers (Topic 606): Narrow-Scope Improvements and Practical Expedients" ("ASU 2016-12") which provides guidance for accounting of credit losses affecting the impairment model for most financial assets and certain other instruments. Entities will be required to use a new forward-looking current expected credit loss model for trade and other receivables, held-to-maturity debt securities, loans and other instruments, which will generally lead to an earlier recognition of loss allowances. Entities will recognize losses on available-for-sale debt securities as allowances rather than a reduction in amortized cost of the security while the measurement process of this loss does not change. Disclosure requirements are expanded regarding an entity’s assumptions, models and methods of estimations of the allowance. The guidance will be effective in the first quarter of 2018, with the option for early adoption. The Company is currently evaluating the impact of this pronouncement on its consolidated financial statements and expects to adopt this pronouncement commencing in the first quarter of 2018. In April 2016, the FASB issued ASU 2016-10, "Identifying Performance Obligations and Licensing" ("ASU 2016-10"). This ASU clarifies two aspects of ASU 2014-09, "Revenue from Contracts with Customers (Topic 606): identifying performance obligations and the licensing implementation guidance". ASU 2016-10 will become effective for the first quarter of 2018. The Company is currently evaluating the impact of this pronouncement on its consolidated financial statements and expects to adopt this pronouncement commencing in the first quarter of 2018. In March 2016, the FASB issued ASU 2016-09, "Compensation - Stock Compensation" ("ASU 2016-09"). This ASU revises the accounting for share-based payment transactions, including the income tax consequences, classification of awards as either equity or liabilities, and an option to recognized gross stock compensation expense with actual forfeitures recognized as they occur, as well as certain classifications on the statement of cash flows. This ASU is effective for annual reporting periods beginning after December 15, 2016, including interim reporting periods within that reporting year, and early adoption is permitted. The Company will adopt this pronouncement commencing in the first quarter of 2017. The Company will apply ASU 2016-09 using a modified retrospective approach and adopt the option to recognize gross stock compensation expense with actual forfeitures recognized as they occur, with the cumulative-effect adjustment to retained earnings, which the Company does not anticipate will have a material impact on its consolidated financial statements. In March 2016, the FASB issued ASU No. 2016-08, "Revenue from Contracts with Customers (Topic 606): Principal versus Agent Considerations (Reporting Revenue Gross versus Net)" ("ASU 2016-08") which clarifies the implementation guidance on principal versus agent considerations. The guidance includes indicators to assist an entity in determining whether it controls a specified good or service before it is transferred to the customers. This guidance will be effective in the first quarter of 2018, with the option to adopt it in the first quarter of 2017. The Company does not anticipate the pronouncement will have a material impact on its consolidated financial statements and expects to adopt this pronouncement commencing in the first quarter of 2018. In February 2016, the FASB issued ASU No. 2016-02, "Leases (Topic 842)." This ASU is a comprehensive new leases standard that amends various aspects of existing guidance for leases and requires additional disclosures about leasing arrangements. It will require companies to recognize lease assets and lease liabilities by lessees for those leases classified as operating leases under previous GAAP. Topic 842 retains a distinction between finance leases and operating leases. The classification criteria for distinguishing between finance leases and operating leases are substantially similar to the classification criteria for distinguishing between capital leases and operating leases in the previous leases guidance. The ASU is effective for annual periods beginning after December 15, 2018, including interim periods within those fiscal years; earlier adoption is permitted. In the financial statements in which the ASU is first applied, leases shall be measured and recognized at the beginning of the earliest comparative period presented with an adjustment to equity. Practical expedients are available for election as a package and if applied consistently to all leases. The Company is currently evaluating the impact of this pronouncement on its consolidated financial statements and expect to adopt this pronouncement commencing in the first quarter of 2019. In November 2015, the FASB issued ASU No. 2015-17, "'Income Taxes (Topic 740): Balance Sheet Classification of Deferred Taxes" ("ASU 2015-17"), which eliminates the current requirement for organizations to present deferred tax liabilities and assets as current and noncurrent in a classified balance sheet. Instead, organizations will be required to classify all deferred tax assets and liabilities as noncurrent. This guidance is effective for public companies financial statements issued for annual periods beginning after December 15, 2016, and interim periods within those annual periods. We do not expect that the adoption of ASU 2015-17 will have a material effect on our consolidated financial statements and will adopt this pronouncement commencing in the first quarter of 2017. In May 2014, the FASB issued ASU No. 2014-9, “Revenue from Contracts with Customers (Topic 606)” ("ASU 2014-9"). ASU 2014-9 outlines a single comprehensive model for entities to use in accounting for revenue arising from contracts with customers and supersedes most current revenue recognition guidance, including industry-specific guidance. This new guidance was to be effective for annual reporting periods (including interim reporting periods within those periods) beginning after December 15, 2017; early adoption was permitted for annual reporting periods beginning after December 15, 2016, including interim reporting periods within those annual periods. Companies have the option of using either a full retrospective or a modified retrospective approach to adopt the guidance. In August 2015, the FASB issued ASU 2015-14 to defer the effective date of the guidance contained in ASU 2014-9 by one year. Thus, the guidance is effective for us commencing in the first quarter of 2018. The Company is currently assessing the impact of this guidance on its results of operations and related disclosures. Based on the procedures performed to date, nothing has come to its attention that would indicate that the adoption of ASU 2014-0

Fair Value Measurements

Fair Value Measurements	12 Months Ended
	Dec. 31, 2016
Fair Value Disclosures [Abstract]
Fair Value Measurements	Fair Value Measurements The Fair Value Measurements topic of the FASB Codification establishes a framework for measuring fair value in accordance with US GAAP, clarifies the definition of fair value within that framework and expands disclosures about fair value measurements. This guidance requires disclosure regarding the manner in which fair value is determined for assets and liabilities and establishes a three-tiered value hierarchy into which these assets and liabilities must be grouped, based upon significant levels of inputs as follows: Level 1—Quoted prices in active markets for identical assets or liabilities. Level 2—Observable inputs, other than Level 1 prices, such as quoted prices in active markets for similar assets and liabilities, quoted prices for identical or similar assets and liabilities in markets that are not active, 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 the fair value of the assets or liabilities. This includes certain pricing models, discounted cash flow methodologies and similar techniques that use significant unobservable inputs. The Company's investment policy is consistent with the definition of available-for-sale securities. All investments have been classified within Level 1 or Level 2 of the fair value hierarchy because of the sufficient observable inputs for revaluation. The Company's Level 1 cash and equivalents and investments are valued using quoted prices that are readily and regularly available in the active market. The Company's Level 2 investments are valued using third-party pricing sources based on observable inputs, such as quoted prices for similar assets at the measurement date; or other inputs that are observable, either directly or indirectly. The following table summarizes, by major security type, the Company's assets that are measured at fair value on a recurring basis and are categorized using the fair value hierarchy and where they are classified on the Consolidated Balance Sheets (in thousands): December 31, 2016 Amortized Cost Gross Unrealized Gains Gross Unrealized Losses Estimated Fair Value Cash and cash equivalents Short-term (1) investments Cash $ 8,504 $ — $ — $ 8,504 $ 8,504 $ — Level 1 securities: Money market funds 28,753 — — 28,753 28,753 — Level 2 securities: Corporate bonds 6,701 — (4 ) 6,697 — 6,697 Agency bond $ 21,548 $ — $ (3 ) $ 21,545 $ — $ 21,545 Total $ 65,506 $ — $ (7 ) $ 65,499 $ 37,257 $ 28,242 December 31, 2015 Amortized Cost Gross Unrealized Gains Gross Unrealized Losses Estimated Fair Value Cash and cash equivalents Short-term (1) investments Cash $ 10,302 $ — $ — $ 10,302 $ 10,302 $ — Level 1 securities: Money market funds 106,883 — — 106,883 106,883 — Total $ 117,185 $ — $ — $ 117,185 $ 117,185 $ — (1) Contractual maturity due within one year.

Accounts Receivable

Accounts Receivable	12 Months Ended
	Dec. 31, 2016
Accounts Receivable, Net, Current [Abstract]
Accounts Receivable	Accounts Receivable Accounts receivable consisted of the following (in thousands): December 31, December 31, Total receivables $ 15,356 $ 15,421 Allowance for doubtful accounts and returns (681 ) (554 ) Accounts receivable, net $ 14,675 $ 14,867 Accounts receivable included unbilled receivable of $2.5 million and $1.3 million for the years ended December 31, 2016 and 2015 . Write-offs related to accounts receivable were approximately $41,000 for the year ended December 31, 2016 , $88,000 for the year ended December 31, 2015 and $70,000 for year ended December 31, 2014 . Summary of allowance for doubtful accounts and returns activity was as follows (in thousands): December 31, 2016 December 31, 2015 Beginning balance $ (554 ) $ (162 ) Provision for bad debts on trade receivables (188 ) (359 ) Other allowances 20 (121 ) Accounts receivable write offs 41 88 Ending balance $ (681 ) $ (554 )

Inventories

Inventories	12 Months Ended
	Dec. 31, 2016
Inventory Disclosure [Abstract]
Inventories	Inventories Inventories consisted of the following (in thousands): December 31, December 31, Raw Material $ 3,331 $ 4,175 Work in process 2,530 2,683 Finished goods 5,859 4,662 Total Inventories $ 11,720 $ 11,520 At December 31, 2016 , inventories included write-downs of $0.2 million related to units affected by the recall and sterilization capacity limitation. At December 31, 2015, inventories included write-downs of $ 0.3 million and reserves of $ 37,000 for estimated surgery cancellations both related to units affected by the recall and sterilization capacity limitation.

Property and Equipment

Property and Equipment	12 Months Ended
	Dec. 31, 2016
Property, Plant and Equipment [Abstract]
Property and Equipment	Property and Equipment Property and equipment consisted of the following (in thousands): Estimated Useful Life (Years) December 31, December 31, Equipment 5-7 $ 16,651 $ 12,185 Furniture and fixtures 5-7 414 391 Computer and software 3 7,027 5,229 Leasehold improvements 2-7 1,294 795 Total property and equipment 25,386 18,600 Accumulated depreciation (10,302 ) (7,634 ) Property and equipment, net $ 15,084 $ 10,966 Depreciation expense related to property and equipment was $2.9 million , $2.4 million and $1.8 million for the years ended December 31, 2016 , 2015 and 2014 , respectively.

Intangible Assets

Intangible Assets	12 Months Ended
	Dec. 31, 2016
Intangible Assets, Net (Excluding Goodwill) [Abstract]
Intangible Assets	Intangible Assets The components of intangible assets consisted of the following (in thousands): Estimated Useful Life (Years) December 31, 2016 December 31, 2015 Developed technology 10 $ 979 $ 979 Accumulated amortization (681 ) (582 ) Developed technology, net 298 397 License agreements 10 1,508 1,508 Accumulated amortization (1,060 ) (910 ) License technology, net 448 598 Intangible assets, net 10 $ 746 $ 995 The Company recognized amortization expense of $0.2 million in the years ended December 31, 2016 , 2015 and 2014 . The weighted-average remaining life of total amortizable intangible assets is 3 years for the developed technology and license agreements. The estimated future aggregated amortization expense for intangible assets owned as of December 31, 2016 consisted of the following (in thousands): Amortization expense 2017 $ 249 2018 249 2019 248 $ 746

Accrued Expenses

Accrued Expenses	12 Months Ended
	Dec. 31, 2016
Accrued Liabilities and Other Liabilities [Abstract]
Accrued Expenses	Accrued Expenses Accrued expenses consisted of the following (in thousands): December 31, December 31, Accrued employee compensation $ 4,037 $ 3,585 Deferred rent 101 213 Accrued legal expense 710 334 Accrued consulting expense 104 134 Accrued vendor charges 1,396 692 Accrued revenue share expense 992 932 Accrued patent settlement and license costs — 500 Accrued clinical trial expense 256 302 Accrued other 896 1,119 $ 8,492 $ 7,811

Deferred Revenue

Deferred Revenue	12 Months Ended
	Dec. 31, 2016
Deferred Revenue Disclosure [Abstract]
Deferred Revenue	Deferred Revenue In connection with the license agreements the Company entered into in April 2015 with Wright Medical and MicroPort (see “Note B — Summary of Significant Accounting Policies”), the Company recognized an initial $5.1 million in aggregate as deferred royalty revenue, of which $4.9 million and $0.2 million is recognized as royalty revenue ratably through 2031 and 2029, respectively.

Commitments and Contingencies

Commitments and Contingencies	12 Months Ended
	Dec. 31, 2016
Commitments and Contingencies Disclosure [Abstract]
Commitments and Contingencies	Commitments and Contingencies Operating Leases - Real Estate The Company maintains its corporate headquarters in a leased building located in Bedford, Massachusetts, and its manufacturing in a facility located in Wilmington, Massachusetts, all of which are accounted for as operating leases. The Company leases the Bedford facility under a non-cancellable sublease that is scheduled to expire in April 2017. The Company leases the Wilmington facility under a long-term, non-cancellable lease that commenced in April 2015 and will expire in July 2022 (the "Wilmington Lease"). The Company also leases satellite facilities under short-term non-cancellable operating leases. On July 25, 2016, the Company entered into an amendment to the Wilmington Lease. Pursuant to the amendment, the Company exercised an option in its current lease to rent an additional 18,223 square feet of space adjacent to the Company’s existing premises. The Company is scheduled to take possession of the additional space in March 2017. On September 19, 2016, the Company entered into a Lease (the "Billerica Lease") with Technology Park X Limited Partnership, for 45,043 square feet of office space in Billerica, Massachusetts. The term of the Billerica Lease commences on April 1, 2017 and expires on October 1, 2025, subject to extension or earlier termination as provided in the Billerica Lease. The Company expects the Billerica property to serve as the Company's corporate headquarters beginning in April 2017. Under the Billerica Lease, the Company will pay no monthly rent for the first six months and approximately $0.1 million per month for the following six months. After April 1, 2018, the Company's monthly rent payments will increase annually by $0.50 per square foot. The Company also will be obligated to pay its pro rata share of certain operating costs, including real estate taxes, under the Billerica Lease. In addition, the Company will post a customary letter of credit in the amount of approximately $0.5 million as a security deposit pursuant to the Billerica Lease, subject to three bi-annual reductions of $0.1 million each beginning on the first day of the 37th month after the Billerica Lease commences. Upon an event of default (as defined in the Billerica Lease), the landlord may terminate the Billerica Lease and require the Company to pay the present value of the remaining rent that would have been payable during the remainder of the term of the Billerica Lease. The Billerica Lease also contains other customary default provisions, representations, warranties, and covenants. On July 25, 2016, the Company entered into an amendment to the Wilmington Lease. Pursuant to the amendment, the Company exercised an option in its current lease to rent an additional 18,223 square feet of space adjacent to the Company’s existing premises. The Company is scheduled to take possession of the additional space in March 2017. The Company has a right to extend the initial term for one additional five -year period. The initial base rental rate for the additional space is $0.2 million annually, subject to 2% annual increases until the expiration of the initial term. The future minimum rental payments under the Company’s non-cancellable operating leases for real estate as of December 31, 2016 were as follows (in thousands): Year Minimum lease Payments 2017 $ 1,179 2018 1,500 2019 1,537 2020 1,574 2021 1,611 2022-2025 4,323 $ 11,724 Rent expense of $1.5 million for the year ended December 31, 2016 , $1.6 million for the year ended December 31, 2015 and $1.5 million for the year ended December 31, 2014 was charged to operations, respectively. The Company’s real estate operating lease agreements contain scheduled rent increases, which are being amortized over the terms of the agreements using the straight-line method. Deferred rent was $0.3 million as of December 31, 2016 , $0.4 million as of December 31, 2015 and $0.5 million and December 31, 2014 . Deferred rent is included in accrued expenses and other long-term liabilities. License and revenue share agreements Revenue share agreements The Company is party to revenue share agreements with certain past and present members of its scientific advisory board under which these advisors agreed to participate on its scientific advisory board and to assist with the development of the Company’s customized implant products and related intellectual property. These agreements provide that the Company will pay the advisor a specified percentage of the Company’s net revenues, ranging from 0.1 % to 1.33 %, with respect to the Company’s products on which the advisor made a technical contribution or, in some cases, which the Company covered by a claim of one of its patents on which the advisor is a named inventor. The specific percentage is determined by reference to product classifications set forth in the agreement and is tiered based on the level of net revenues collected by the Company on such product sales. The Company’s payment obligations under these agreements typically expire a fixed number of years after expiration or termination of the agreement, but in some cases expire on a product-by-product basis or expiration of the last to expire of the Company’s patents where the advisor is a named inventor that claims the applicable product. Philipp Lang, M.D., one of the Company’s directors and former Chief Executive Officer and current director, joined the Company’s scientific advisory board in 2004 prior to becoming an employee. The Company entered into a revenue share agreement with Dr. Lang in 2008 when he became the Company’s Chief Executive Officer. In 2011, the Company entered into an amended and restated revenue share agreement with Dr. Lang. Under this agreement, the specified percentage of the Company’s net revenues payable to Dr. Lang ranges from 0.875 % to 1.33 % and applies to all of the Company’s current products, including the Company’s iUni, iDuo, iTotal Cr, and iTotal PS products, as well as certain other knee, hip and shoulder replacement products and related instrumentation the Company may develop in the future. The Company’s payment obligations under this agreement expire on a product-by-product basis on the last to expire of the Company’s patents on which Dr. Lang is named an inventor that claim the applicable product. These payment obligations survived termination of Dr. Lang’s employment with the Company. The Company incurred revenue share expense paid to Dr. Lang of $1.0 million , $0.8 million and $0.6 million for the years ended December 31, 2016 , 2015 and 2014 , respectively. The Company incurred aggregate revenue share expense including all amounts payable under the Company’s scientific advisory board and Dr. Lang revenue share agreements of $3.5 million during the year ended December 31, 2016 , representing 4.4% of product revenue, $3.2 million during the year ended December 31, 2015 , representing 5.0% of product revenue, and $2.3 million during the year ended December 31, 2014 , representing 4.7% of product revenue. Revenue share expense is included in research and development. See “Note L—Related Party Transactions” for further information regarding the Company’s arrangement with Dr. Lang. Other obligations In the ordinary course of business, the Company is a party to certain non-cancellable contractual obligations typically related to research and development and marketing services. 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. The following table summarizes the Company's contractual obligations as of the year ended December 31, 2016 (in thousands): Payment Due by Period Contractual Obligations Total Less than 1 year Years 1 to 3 Years 3 to 5 After 5 years Operating lease obligations - real estate (1) 11,724 1,179 3,037 3,185 4,323 Other (2) 1,418 484 409 400 125 Total (3) $ 13,142 $ 1,663 $ 3,446 $ 3,585 $ 4,448 (1) Represents operating lease commitments for office and manufacturing space in Bedford, Wilmington and Billerica, Massachusetts. (2) Represents amounts payable under our product royalty agreements, operating leases for office equipment and a software development collaboration project (3) This table does not include: (a) revenue share obligations to past and present members of our scientific advisory board and one of our directors, as the amounts of such payments are not known with certainty; and (b) contracts that are entered into in the ordinary course of business that are not material in the aggregate in any period presented above. See "—Revenue share agreements" and "Certain Relationships and Related-Persons Transactions—Revenue share agreement with Dr. Lang" for a description of our revenue share arrangements. There have been no contingent liabilities requiring accrual at December 31, 2016 or December 31, 2015 . Legal proceedings In the ordinary course of the Company's business, the Company is subject to litigation, claims and administrative proceedings on a variety of matters, including patent infringement, product liability, securities-related claims, and other claims in the United States and in other countries where the Company sells its products. An estimate of the possible loss or range of loss as a result of any of these matters cannot be made; however, management does not believe that these matters, individually or in the aggregate, are material to its financial condition, results of operations or cash flows. On September 3, 2015, a purported securities class action lawsuit was filed against the Company, the Company's Chief Executive Officer, and Chief Financial Officer in the United States District Court for the District of Massachusetts, which has since been dismissed. The complaint was brought on behalf of an alleged class of those who purchased the Company's common stock in connection with the Company's initial public offering or on the open market between July 1, 2015 and August 28, 2015, which the Company refer to as the class period. On November 2, 2015, two motions were filed on behalf of persons seeking to be named as lead plaintiff in the litigation. On January 11, 2016, a consolidated amended complaint was filed purporting to allege claims arising under Sections 11 and 15 of the Securities Act of 1933, as amended, Sections 10(b) and 20(a) of the Securities Exchange Act of 1934, as amended, and Rule 10b-5 promulgated thereunder, including allegations that the Company's stock was artificially inflated during the class period because the defendants allegedly made misrepresentations or did not make proper disclosures regarding the Company's manufacturing process prior to the Company's voluntary recall of specific serial numbers of patient-specific instrumentation for certain of the Company's knee replacement product systems. The complaint sought, among other relief, certification of the class, unspecified compensatory damages, interest, attorneys’ fees, expert fees and other costs. On March 18 2016, the Company filed a motion to dismiss all of the claims of the consolidated amended complaint. On August 3, 2016, the court granted the Company's motion to dismiss the class action in its entirety and denied the plaintiffs’ request to replead their allegations. The plaintiffs did not file an appeal, and the time for filing an appeal has expired. On February 29, 2016, the Company filed a lawsuit against Smith & Nephew, Inc. (“Smith & Nephew”) in the United States District Court for the District of Massachusetts Eastern Division, which was amended on June 13, 2016 (the "Smith & Nephew Lawsuit"). The Smith & Nephew Lawsuit alleges that Smith & Nephew’s Visionaire® patient-specific instrumentation as well as the implants systems used in conjunction with the Visionaire instrumentation infringe nine of the Company's patents, and it requests, among other relief, monetary damages for willful infringement, enhanced damages and a permanent injunction. On May 27, 2016, Smith & Nephew filed an Answer and Counterclaims in response to the Company's lawsuit, which it subsequently amended on July 22, 2016. Smith & Nephew denied that its Visionaire® patient-specific instrumentation as well as the implants systems used in conjunction with the Visionaire instrumentation infringe the patents asserted by the Company in the lawsuit. It also alleged two affirmative defenses: that the Company's asserted patents are invalid and that the Company is barred from relief under the doctrine of laches. In addition, Smith & Nephew asserted a series of counterclaims, including counterclaims seeking declaratory judgments that Smith & Nephew’s accused products do not infringe the Company's patents and that the Company's patents are invalid. Smith & Nephew also alleged that ConforMIS infringes ten patents owned or exclusively licensed by Smith & Nephew: two patents that Smith & Nephew alleges are infringed by the Company's iUni and iDuo products; three patents that Smith & Nephew alleges are infringed by the Company's iTotal products; and five patents that Smith & Nephew licenses from Kinamed, Inc. of Camarillo, California and that it alleges are infringed by the Company's iUni, iDuo and iTotal products. Due to Smith & Nephew’s licensing arrangement with Kinamed, Kinamed has been named as a party to the lawsuit. Smith & Nephew and Kinamed have requested, among other relief, monetary damages for willful infringement, enhanced damages and a permanent injunction. An adverse outcome of this lawsuit could have a material adverse effect on the Company's business, financial condition or results of operations. The Company is presently unable to predict the outcome of the lawsuit or to reasonably estimate a range of potential losses, if any, related to the lawsuit. Between September 21, 2016 and February 28, 2017, Smith & Nephew filed 14 petitions with the United States Patent & Trademark Office (“USPTO”) requesting Inter Partes Review of eight of the nine patents that the Company asserted in against Smith & Nephew in the lawsuit. In its petition, Smith & Nephew alleges that the Company's patents are obvious in light of certain prior art. The Company expects that Smith & Nephew will file additional petitions with the USPTO requesting Inter Partes Review of some or all of the patents that the Company has asserted in the Smith & Nephew Litigation. On January 27, 2017, Smith & Nephew filed a motion seeking a stay of the Smith & Nephew Lawsuit until any requested Inter Partes Reviews are resolved, and the Company filed an opposition to that motion. The Company is presently unable to predict the outcome of the motion to stay the proceedings, the existing petitions requesting Inter Partes Review of the Company's patents, or of any other petitions requesting Inter Partes Review that Smith & Nephew or any other party may file, including whether the USPTO will institute any of the requested Inter Partes Reviews, or, if instituted, the outcome of any such Inter Partes Reviews. An adverse outcome of some or all of these potential Inter Partes Review proceedings could have a material adverse effect on the Company's business, financial condition or results of operations. Legal costs associated with legal proceedings are accrued as incurred. Indemnifications In the normal course of business, the Company enters into contracts and agreements that contain a variety of representations and warranties and provide for general indemnifications. The Company’s exposure under these agreements is unknown because it involves claims that may be made against the Company in the future, but have not yet been made. To date, the Company has not paid any claims or been required to defend any action related to its indemnification obligations. However, the Company may record charges in the future as a result of these indemnification obligations. In accordance with its bylaws, the Company has indemnification obligations to its officers and directors for certain events or occurrences, subject to certain limits, while they are serving at the Company’s request in such capacity. There have been no claims to date and the Company has a director and officer insurance policy that enables it to recover a portion of any amounts paid for future claims.

Debt and Notes Payable

Debt and Notes Payable	12 Months Ended
	Dec. 31, 2016
Debt Disclosure [Abstract]
Debt and Notes Payable	Debt and Notes Payable $1.4 million term loan—Massachusetts Development Finance Agency In June 2011, the Company entered into a $1.4 million term loan facility with Massachusetts Development Finance Agency (“MDFA”) for the purposes of equipment purchases. At December 31, 2015 , there was $0.5 million outstanding under the MDFA facility, which was secured on a second-lien basis by certain tangible assets of the Company. The Company voluntarily prepaid the then-remaining loan balance of $0.2 million in December 2016. At the time the Company entered into the MDFA facility, the Company borrowed the first tranche of $0.6 million , with the remaining funds to be borrowed over the following 18 months . To date, the Company borrowed a total of $1.4 million of the available commitments under the facility. Loans under the MDFA facility bear a fixed interest rate of 6.5% per annum. Interest is payable monthly in arrears. Beginning on January 1, 2013, the Company began making payments of principal and interest in 66 equal monthly installments. In connection with the MDFA facility, the Company issued warrants to MDFA to purchase 16,000 shares of Series D preferred stock. Based on the Company’s assessment of the warrants relative to ASC 480, Distinguishing Liabilities from Equity , the warrants are classified as equity and the Company recorded fair value of $46,000 as a discount to the term loan and was amortized to interest expense over the 84 -month life of the term loan and the unamortized portion was expensed when the debt was voluntarily paid in December 2016.

Related Party Transactions

Related Party Transactions	12 Months Ended
	Dec. 31, 2016
Related Party Transactions [Abstract]
Related Party Transactions	Related Party Transactions Vertegen In April 2007, the Company entered into a license agreement with Vertegen, Inc., or Vertegen, which was amended in May 2015 (the “Vertegen Agreement”). Vertegen is an entity that is wholly owned by Dr. Lang, one of the Company’s directors and the Company's former Chief Executive Officer. Under the Vertegen Agreement, Vertegen granted the Company an exclusive, worldwide license under specified Vertegen patent rights and related technology to make, use and sell products and services in the fields of diagnosis and treatment of articular disorders and disorders of the human spine. The Company may sublicense the rights licensed to it by Vertegen. The Company is required to use commercially reasonable efforts, at its sole expense, to prosecute the patent applications licensed to the Company by Vertegen. In connection with entering into the license agreement with Vertegen, the Company paid Vertegen an initial license fee of $10,000 and issued Vertegen a warrant to purchase 100,000 shares of its common stock at an exercise price of $1.10 per share, which has expired unexercised. Pursuant to the Vertegen Agreement, the Company is required to pay Vertegen a 6% royalty on net sales of products covered by the patents licensed to us by Vertegen, the subject matter of which is directed primarily to spinal implants, and any proceeds from the Company enforcing the patent rights licensed to the Company by Vertegen. Such 6% royalty rate will be reduced to 3% in the United States during the five -year period following the expiration of the last-to-expire applicable patent in the United States and in the rest of the world during the five -year period following the expiration of the last-to-expire patent anywhere in the world. The Company has not sold any products subject to this agreement and has paid no royalties under this agreement. The Company has cumulatively paid approximately $150,000 in expenses as of December 31, 2016 and $140,000 as of December 31, 2015 and December 31, 2014 in connection with the filing and prosecution of the patent applications licensed to the Company by Vertegen. The Vertegen Agreement may be terminated by the Company at any time by providing notice to Vertegen. In addition, Vertegen may terminate the Vertegen Agreement in its entirety if the Company is in material breach of the agreement, and the Company fails to cure such breach during a specified period. Revenue share agreements As described in Note J, the Company is a party to certain agreements with advisors to participate as a member of the Company’s scientific advisory board. In September 2011, the Company entered into an amended and restated revenue share agreement with Philipp Lang, M.D., one of the Company’s directors and former Chief Executive Officer, which amended and restated a similar agreement entered into in 2008 when Dr. Lang stepped down as chair of the Company’s scientific advisory board and became the Company’s Chief Executive Officer. This agreement provides that the Company will pay Dr. Lang a specified percentage of our net revenues, ranging from 0.875 % to 1.33 %, with respect to all of our current and planned products, including the Company’s iUni, iDuo, iTotal CR, and iTotal PS products, as well as certain other knee, hip and shoulder replacement products and related instrumentation the Company may develop in the future. The specific percentage is determined by reference to product classifications set forth in the agreement and is tiered based on the level of net revenues collected by the Company on such product sales. The Company’s payment obligations expire on a product-by-product basis on the last to expire of the Company’s patents on which Dr. Lang is a named inventor that claim the applicable product. These payment obligations survived the termination of Dr. Lang’s employment with the Company. The Company incurred revenue share expense paid to Dr. Lang of $1.0 million , $0.8 million and $0.6 million for the years ended December 31, 2016 , 2015 and 2014 , respectively.

Stockholders' Equity

Stockholders' Equity	12 Months Ended
	Dec. 31, 2016
Stockholders' Equity Note [Abstract]
Shareholders' Equity	Stockholders’ Equity Common stock Common stockholders are entitled to dividends as and when declared by the board of directors, subject to the rights of holders of all classes of stock outstanding having priority rights as to dividends. There have been no dividends declared to date. The holder of each share of common stock was entitled to one vote. Summary of common stock activity was as follows: Shares Outstanding December 31, 2014 4,286,164 Issuance of common stock - option & warrant exercises 395,192 Issuance of restricted common stock 174,530 Issuance of common stock - IPO 10,350,000 Issuance of common stock - preferred stock conversion to common stock 25,904,241 Outstanding December 31, 2015 41,110,127 Issuance of common stock - option & warrant exercises 1,485,401 Issuance of restricted common stock 804,019 Outstanding December 31, 2016 43,399,547 Preferred stock The Company’s Restated Certificate of Incorporation authorizes the Company to issue 5,000,000 shares of preferred stock, $0.00001 par value, all of which is undesignated. No shares were issued and outstanding at December 31, 2016 and December 31, 2015 . Demand registration rights In conjunction with the IPO, the Company entered into an Amended and Restated Information and Registration Rights Agreement effective June 29, 2015 (the “Registration Rights Agreement”), which provided, among other things, registration rights to certain investors that had held the Company's preferred stock prior to the IPO. Subject to specified limitations set forth in a registration rights agreement, at any time, the holders of at least 25% of the then outstanding registrable shares may at any time demand in writing that the Company register all or a portion of the registrable shares under the Securities Act on a Form other than Form S-3 for an offering of at least 20% of the then outstanding registrable shares or a lesser percentage of the then outstanding registrable shares provided that it is reasonably anticipated the aggregate offering price would exceed $20 million . The Company is not obligated to file a registration statement pursuant to these rights on more than two occasions. In addition, after such time as the Company is eligible to use Form S-3, subject to specified limitations set forth in the registration rights agreement, the holders of at least 25% of the then outstanding registrable shares may at any time demand in writing that the Company register all or a portion of the registrable shares under the Securities Act on Form S-3 for an offering of at least 25% of the then outstanding registrable shares having an anticipated aggregate offering price to the public, net of selling expenses, of at least $5 million (a “Resale Registration Statement”). The Company is not obligated to effect a registration pursuant to a Resale Registration Statement on more than one occasion. Incidental registration rights If, at any time the Company proposes to file a registration statement to register any of its common stock under the Securities Act in connection with a public offering of such common stock, other than pursuant to certain specified registrations, the holders of registrable shares are entitled to notice of registration and, subject to specified exceptions, including market conditions, the Company will be required, upon the holder’s request, to register their then held registrable shares. Warrants The Company also issued warrants to certain investors and consultants to purchase shares of the Company’s preferred stock and common stock. Based on the Company’s assessment of the warrants granted in 2013 and 2014 relative to ASC 480, Distinguishing Liabilities from Equity , the warrants are classified as equity. No new warrants were issued in the years ended December 31, 2016 and 2015 . According to ASC 480, an entity shall classify as a liability any financial instrument, other than an outstanding share, that, at inception, both a) embodies an obligation to repurchase the issuer’s equity shares, or is indexed to such obligation and b) requires or may require the issuer to settle the obligation by transferring assets. The warrants do not contain any provision that requires the Company to repurchase the shares and are not indexed to such an obligation. The warrants also do not require the Company to settle by transferring assets. All warrants were exercisable immediately upon issuance. Upon the conversion of the Company’s preferred stock into common stock in connection with the closing of the Company’s IPO, all outstanding warrants to purchase preferred stock instead became warrants to purchase shares of common stock at a ratio of one share of common stock for every two shares of preferred stock. The fair value of warrants at date of grant was estimated using the Black-Scholes option pricing model, based on the following assumptions in the year ended December 31, 2014: Risk-free interest rate 0.91%-1.71% Expected term (in years) 2.50-5.00 Dividend yield —% Expected volatility 50.00%-55.00% Common stock warrants The Company also issued warrants to certain investors and consultants to purchase 1,138,424 shares of common stock at an exercise price range of $0.02 to $9.00 per share. Additionally, certain warrants to purchase shares of preferred stock were converted to 564,188 warrants to purchase 564,188 shares of common stock. Warrants to purchase 171,783 shares of common stock were outstanding as of December 31, 2016 and 751,779 shares of common stock were outstanding as of December 31, 2015 . Outstanding warrants are currently exercisable with varying exercise expiration dates from 2017 through 2024. Summary of common stock warrant activity was as follows: Number of Warrants Weighted Average Exercise Price Per Share Number of Warrants Exercisable Weighted Average Price Per Share Weighted Average Contractual Life Outstanding December 31, 2014 204,312 $ 8.90 204,312 $ 8.90 3.26 Exercised (16,721 ) 7.80 (16,721 ) 7.80 — Converted from preferred warrant 564,188 10.73 564,188 10.73 — Outstanding December 31, 2015 751,779 $ 10.30 751,779 $ 10.30 1.33 Exercised (166,665 ) 9.00 (166,665 ) 9.00 — Cancelled/expired (413,331 ) — (413,331 ) — — Outstanding December 31, 2016 171,783 $ 7.47 171,783 $ 7.47 1.62 Stock option plans In June 2004, the Company authorized the adoption of the 2004 Stock Option and Incentive Plan (the “2004 Plan”). Under the 2004 Plan, options were granted to persons who were, at the time of grant, employees, officers, or directors of, or consultants or advisors to, the Company. The 2004 Plan provided for the granting of non-statutory options, incentive options, stock bonuses, and rights to acquire restricted stock. The option price at the date of grant was determined by the Board of Directors and, in the case of incentive options, could not be less than the fair market value of the common stock at the date of grant, as determined by the Board of Directors. Options granted under the 2004 Plan generally vest over a period of four years and are set to expire ten years from the date of grant. In February 2011, the Company terminated the 2004 Plan and all options outstanding under it were transferred to the 2011 Stock Option/Stock Issuance Plan (the “2011 Plan”). In February 2011, the Company authorized the adoption of the 2011 Plan. The 2011 Plan is divided into two separate equity programs, Option Grant Program and Stock Issuance Program. Per the 2011 Plan, options can be granted to persons who are, at the time, employees, officers, or directors of, or consultants or advisors to, the Company. The 2011 Plan provides for the granting of non-statutory options, incentive options and common stock. The price at the date of grant is determined by the Board of Directors and, in the case of incentive options and common stock, cannot be less than the fair market value of the common stock at the date of grant, as determined by the Board of Directors. Options granted under the 2011 Plan generally vest over a period of four years and expire ten years from the date of grant. In June 2015, the Company terminated the 2011 Plan and all options outstanding under it were transferred to the 2015 Stock Incentive Plan (the “2015 Plan”). The 2015 Plan provides for the grant of incentive stock options, nonstatutory stock options, stock appreciation rights, restricted stock awards, restricted stock units and other stock-based awards. The number of shares of our common stock that will be reserved for issuance under the 2015 Plan is the sum of: (1) 2,000,000 ; plus (2) the number of shares equal to the sum of the number of shares of our common stock then available for issuance under the 2011 Plan and the number of shares of our common stock subject to outstanding awards under the 2011 Plan or under the 2004 Plan that expire, terminate or are otherwise surrendered, canceled, forfeited or repurchased by us at their original issuance price pursuant to a contractual repurchase right; plus (3) an annual increase, to be added on the first day of each fiscal year, beginning with the fiscal year ending December 31, 2016 and continuing until, and including, the fiscal year ending December 31, 2025, equal to the least of (a) 3,000,000 shares of our common stock, (b) 3% of the number of shares of our common stock outstanding on the first day of such fiscal year and (c) an amount determined by the Board. Our employees, officers, directors, consultants and advisors will be eligible to receive awards under the 2015 Plan. Incentive stock options, however, may only be granted to our employees. Options and restricted stock awards granted under the 2015 Plan generally vest over a period of four years and expire ten years from the date of grant. As of December 31, 2016 , 1,318,370 shares of common stock were available for future issuance under the 2015 Plan. Activity under all stock option plans was as follows: Number of Options Weighted Average Exercise Price per Share Aggregate Intrinsic Value (In Thousands) Outstanding December 31, 2013 4,869,330 $ 3.77 Granted 1,037,547 9.77 Exercised (118,738 ) 1.50 Expired (142,206 ) 5.29 Cancelled/Forfeited (290,366 ) 5.08 Outstanding December 31, 2014 5,355,567 $ 4.87 Granted 403,086 12.20 Exercised (383,458 ) 2.10 Expired (30,876 ) 5.97 Cancelled/Forfeited (95,990 ) 7.42 Outstanding December 31, 2015 5,248,329 $ 5.56 Granted 179,178 8.78 Exercised (1,467,692 ) 2.78 8,219 Expired (81,251 ) 9.70 Cancelled/Forfeited (88,524 ) 9.93 Outstanding December 31, 2016 3,790,040 $ 6.60 $ 8,547 Total vested and exercisable 3,231,167 $ 6.01 $ 8,514 The total fair value of stock options that vested during the year ended December 31, 2016 was $1.9 million . The weighted average remaining contractual term for the total stock options outstanding was 5.55 years at December 31, 2016 . The weighted average remaining contractual term for the total stock options vested and exercisable was 5.06 years at December 31, 2016 . Restricted common stock award activity under the plan was as follows: Number of Shares Weighted Average Fair Value Unvested December 31, 2014 — $ — Granted 174,530 22.31 Unvested December 31, 2015 174,530 $ 22.31 Granted 873,589 8.61 Vested (66,839 ) 17.72 Forfeited (69,570 ) 11.83 Unvested December 31, 2016 911,710 $ 10.32 The total fair value of restricted common stock options that vested during the year ended December 31, 2016 was $ 0.7 million . Stock-based compensation The Company uses the Black-Scholes option pricing model to determine the fair value of stock options. The determination of the fair value of stock-based payment awards on the date of grant using a pricing model is affected by the value of the Company’s common stock as well as assumptions regarding a number of complex and subjective variables. The valuation of the Company’s common stock prior to the IPO was performed with the assistance of an independent third-party valuation firm using a methodology that includes various inputs including the Company’s historical and projected financial results, peer company public data and market metrics, such as risk-free interest and discount rates. As the valuations included unobservable inputs that were primarily based on the Company’s own assumptions, the inputs were considered level 3 inputs within the fair value hierarchy. The weighted average fair value of options granted was $4.46 for the year ended December 31, 2016 , $5.52 for the year ended December 31, 2015 and $4.40 for the year ended December 31, 2014 . The fair value of options at date of grant was estimated using the Black-Scholes option pricing model, based on the following assumptions: Years Ended December 31, 2016 2015 2014 Risk-free interest rate 1.98% 1.37% - 1.77% 1.66% - 2.29% Expected term (in years) 6.25 5.47 - 6.45 5.00 - 7.25 Dividend yield —% —% —% Expected volatility 51.00% 49.00% - 50.00% 50.00% Risk-free interest rate. The risk-free interest rate is based on U.S. Treasury zero-coupon issues with remaining terms similar to the expected term on the options. Expected term. The expected term of stock options represents the period the stock options are expected to remain outstanding and is based on the “SEC Shortcut Approach” as defined in “Share-Based Payment” (SAB 107) ASC 718-10-S99, “Compensation—Stock Compensation—Overall—SEC Materials ,” which is the midpoint between the vesting date and the end of the contractual term. With certain stock option grants, the exercise price may exceed the fair value of the common stock. In these instances, the Company adjusts the expected term accordingly. Dividend yield. The Company has never declared or paid any cash dividends and does not plan to pay cash dividends in the foreseeable future, and, therefore, used an expected dividend yield of zero in the valuation model. Expected volatility. Expected volatility measures the amount that a stock price has fluctuated or is expected to fluctuate during a period. The Company does not have sufficient history of market prices of its common stock as it is a newly public company. Therefore, the Company estimates volatility using historical volatilities of similar public entities. Forfeitures. The Company uses historical data to estimate pre-vesting option forfeitures and record stock-based compensation expense only for those awards that are expected to vest. If the Company’s actual forfeiture rate is materially different from its estimate, the stock-based compensation expense could be significantly different from what the Company has recorded in the current period. Stock-based compensation expense was $5.3 million , $3.6 million and $2.6 million for the years ended December 31, 2016 , 2015 and 2014 , respectively. Stock-based compensation expense was calculated based on awards ultimately expected to vest. To date, the amount of stock-based compensation capitalized as part of inventory was not material. The following is a summary of stock-based compensation expense (in thousands): Years Ended December 31, 2016 2015 2014 Cost of revenues $ 333 $ 239 $ 162 Sales and marketing 1,197 730 597 Research and development 1,466 784 628 General and administrative 2,328 1,854 1,163 $ 5,324 $ 3,607 $ 2,550 At December 31, 2016 , the Company had $2.2 million of total unrecognized compensation expense for options that will be recognized over a weighted average period of 2.35 years. At December 31, 2016 , the Company had $ 7.1 million of total unrecognized compensation expense for restricted awards recognized over a weighted average period of 2.44 years.

Income Taxes

Income Taxes	12 Months Ended
	Dec. 31, 2016
Income Tax Disclosure [Abstract]
Income Taxes	Income Taxes The Company files U.S. federal and state tax returns as well as foreign income tax returns. The Company has accumulated significant losses since its inception in 2004. For financial reporting purposes, income (loss) before income taxes for the years ended December 31, 2016 , 2015 and 2014 include the following components (in thousands): Years ended December 31, 2016 2015 2014 Income (loss) from continuing operations before income taxes: U.S. $ (51,576 ) $ (50,155 ) $ (40,328 ) Non‑U.S. (5,949 ) (7,050 ) (5,353 ) $ (57,525 ) $ (57,205 ) $ (45,681 ) Significant components of the provision for income taxes for the years ended December 31, 2016 , 2015 and 2014 were as follows (in thousands): Years ended December 31, 2016 2015 2014 Current: Federal $ — $ — $ — State — — — Foreign 63 41 41 63 41 41 Deferred: Federal — — — State — — — Foreign — — — Total $ 63 $ 41 $ 41 The Company accounts for income taxes under FASB ASC 740 Accounting for Income Taxes . Deferred tax assets and liabilities are determined based upon differences between financial reporting and tax bases of assets and liabilities and are measured using the enacted tax rates and laws that will be in effect when the differences are expected to reverse. A reconciliation of the income tax expense (benefit) at the statutory federal income tax rate as reflected in the financial statements was as follows: Years ended December 31, 2016 2015 2014 Tax at U.S. statutory rate (34.00 )% (34.00 )% (34.00 )% State taxes, net of federal benefits (2.70 ) (2.27 ) (2.36 ) Permanent items 0.42 1.52 1.46 Tax credit (1.06 ) (0.85 ) (8.59 ) Change in valuation allowance 33.95 31.07 37.49 Foreign rate differential 1.04 1.68 0.68 Rate change (0.06 ) 0.01 (0.02 ) Uncertain tax positions 2.06 2.21 2.97 Other 0.46 0.7 2.47 0.11 % 0.07 % 0.10 % Deferred income taxes reflect the net tax effects of temporary differences between the carrying amount of assets and liabilities for financial reporting purposes and the amounts used for income tax purposes. Significant components of the Company’s deferred tax assets (liabilities) consisted of the following (in thousands): Years ended December 31, 2016 2015 Deferred tax assets: Federal and state net operating loss carryforwards $ 115,719 $ 99,823 Foreign net operating loss carryforwards 2,561 2,973 Accrued expenses 280 — Credits 5,091 4,483 Deferred revenue 1,709 — Other 5,703 4,138 Total deferred tax assets 131,063 111,417 Valuation allowance (130,005 ) (110,518 ) Net deferred tax assets 1,058 899 Deferred tax liabilities: Fixed assets (841 ) (612 ) Intangibles (217 ) (287 ) Other — — Net deferred tax liabilities (1,058 ) (899 ) Net deferred tax assets $ — $ — Current net deferred tax asset 33 15 Long‑term net deferred tax liability (33 ) (15 ) Net deferred tax asset $ — $ — A valuation allowance is required to reduce the deferred tax assets reported if, based on weight of evidence, it is more likely than not that some portion or all of the deferred tax assets will not be realized. After consideration of all of the evidence, both positive and negative, the Company determined that a $130.0 million valuation allowance at December 31, 2016 was necessary to reduce the deferred tax assets to the amount that will more likely than not be realized. The change in the valuation allowance for the current year was $19.5 million . The Company provided a valuation allowance for the full amount of its net deferred tax asset for all periods because realization of any future tax benefit cannot be sufficiently assured as the Company does not expect income in the near term. At December 31, 2016 , the Company had approximately $323.6 million of federal net operating loss carryforwards and approximately $168.0 million of state net operating loss carryforwards that if not utilized, will begin to expire in 2020 for federal tax purposes and continue to expire at various dates for state tax purposes. The utilization of such net operating loss carryforwards and realization of tax benefits in future years depends predominantly upon having taxable income. Utilization of the NOL and credits may be subject to a substantial annual limitation due to ownership change limitations that have occurred or that could occur in the future, as required by Section 382 and Section 383 of the Code. These ownership changes may limit the amount of NOL that can be utilized annually to offset future taxable income and tax, respectively. In general, an “ownership change” as defined by Section 382 of the Code results from a transaction or series of transactions over a three‑year period resulting in an ownership change of more than 50 percentage points of the outstanding stock of a company by certain stockholders. The Company has completed a study to assess whether an ownership change has occurred or whether there have been multiple ownership changes since its formation. The results of this study indicated that the Company experienced ownership changes as defined by Section 382 of the Code. The Company has not identified NOLs or credits that, as a result of these restrictions, will expire unused. The Company also had foreign net operating losses of approximately $24.7 million as of December 31, 2016 , which may be available to offset future income recognized in the Federal Republic of Germany . The net operating losses in Germany have indefinite carryforward periods. The Company has adopted the accounting guidance related to uncertainty in income taxes. The total liability for unrecognized income tax benefits was approximately $4.9 million as of December 31, 2016 , $3.7 million as of December 31, 2015 and $2.5 million of December 31, 2014 . Of the total liability at December 31, 2016 and 2015 , $4.8 million and $3.6 million , respectively, were netted against deferred tax assets. The Company recognizes interest accrued and penalties, if applicable, related to unrecognized tax benefits in income tax expense. The Company does not expect any significant changes in the next 12 months. Unrecognized tax benefits during the three years ended December 31, 2016 , 2015 and 2014 consisted of the following: Years ended December 31, 2016 2015 2014 Unrecognized tax benefits beginning of year $ 3,730 $ 2,466 $ 1,109 Gross change for current year positions 1,187 1,264 1,357 Decrease for prior period positions — — — Decrease due to settlements and payments — — — Decrease due to statute limitations — — — Unrecognized tax benefits end of the year $ 4,917 $ 3,730 $ 2,466 As of December 31, 2016 , the Company was open to examination in the U.S. federal and certain state jurisdictions for all of the Company’s tax years since the net operating losses may potentially be utilized in future years to reduce taxable income. The Company was open to examination for tax years 2007 through 2015 in Germany and tax years 2013 through 2015 in the UK. At December 31, 2016 , foreign earnings, which were not significant, have been retained indefinitely by foreign subsidiary companies for reinvestment; therefore, no provision has been made for income taxes that would be payable upon the distribution of such earnings, and it would not be practicable to determine the amount of the related unrecognized deferred income tax liability. Upon repatriation of those earnings, in the form of dividends or otherwise, the Company would be subject to U.S. federal income taxes (subject to an adjustment for foreign tax credits) and withholding taxes payable to the various foreign countries.

Segment and Geographic Data

Segment and Geographic Data	12 Months Ended
	Dec. 31, 2016
Segment Reporting [Abstract]
Segment and Geographic Data	Segment and Geographic Data The Company operates as one reportable segment as described in Note B to the Consolidated Financial Statements. The countries in which the Company has local revenue generating operations have been combined into the following geographic areas: the United States (including Puerto Rico), Germany and the rest of the world, which consists of Europe predominately (including the United Kingdom) and other foreign countries. Sales are attributable to a geographic area based upon the customer’s country of domicile. Net property, plant and equipment are based upon physical location of the assets. Geographic information consisted of the following (in thousands): Years Ended December 31, 2016 2015 2014 Product Revenue United States $ 62,366 $ 47,223 $ 34,350 Germany 14,701 13,795 12,549 Rest of World 1,854 1,773 1,287 $ 78,921 $ 62,791 $ 48,186 December 31, 2016 2015 Property and equipment, net United States $ 14,971 $ 10,836 Rest of World 113 130 $ 15,084 $ 10,966

Employee Savings Plan

Employee Savings Plan	12 Months Ended
	Dec. 31, 2016
Compensation and Retirement Disclosure [Abstract]
Compensation and Employee Benefit Plans	Employee Savings Plan We have established an employee savings plan pursuant to Section 401(k) of the Internal Revenue Code. The plan allows participating employees to deposit into tax deferred investment accounts up to 80% of eligible earnings, subject to annual limits. We make contributions to the plan in an amount equal to 50% of elective deferrals on up to 4% of the participant’s eligible earnings. We contributed approximately $478,000 , $400,000 and $377,000 to the plan during the years ended December 31, 2016 , 2015 and 2014 , respectively.

Selected Quarterly Financial In

Selected Quarterly Financial Information (Unaudited)	12 Months Ended
	Dec. 31, 2016
Quarterly Financial Information Disclosure [Abstract]
Selected Quarterly Financial Information	Selected Quarterly Financial Information (Unaudited) Three Months Ended December 31, 2016 September 30, 2016 June 30, 2016 March 31, 2016 Total revenue $ 21,673 $ 18,643 $ 19,333 $ 20,250 Gross profit 8,045 5,998 6,001 6,663 Net loss (15,705 ) (12,762 ) (14,052 ) (15,034 ) Net loss per share - basic and diluted $ (0.37 ) $ (0.31 ) $ (0.34 ) $ (0.37 ) Three Months Ended December 31, 2015 September 30, 2015 June 30, 2015 March 31, 2015 Total revenue $ 19,071 $ 13,894 $ 19,222 $ 14,700 Gross profit 6,340 2,762 7,827 4,856 Net loss (14,990 ) (17,107 ) (10,892 ) (14,257 ) Net loss per share - basic and diluted $ (0.37 ) $ (0.45 ) $ (2.51 ) $ (3.32 )

Subsequent Events

Subsequent Events	12 Months Ended
	Dec. 31, 2016
Subsequent Events [Abstract]
Subsequent Events	Subsequent Events 2017 Secured Loan Agreement On January 6, 2017, we entered into a senior secured $50 million loan and security agreement with Oxford. Through the term loan facility with Oxford, the Company initially accessed $15 million of borrowings and an additional funding of $15 million is available to the Company, at its option, through December 2017 and an additional $20 million is available through June 2018, in each case, subject to the satisfaction of certain revenue milestones and customary drawdown conditions. The credit facility is secured by substantially all of the Company’s personal property other than the Company’s intellectual property. Under the terms of the credit facility, the Company cannot grant a security interest in its intellectual property to any other party. The term loan under the credit facility bears interest at a floating annual rate calculated at the greater of 30 day LIBOR or 0.53% , plus 6.47% . The Company is required to make monthly interest only payments in arrears commencing on the second payment date following the funding date of each term loan, and continuing on the payment date of each successive month thereafter through and including the payment date immediately preceding the amortization date of February 1, 2019 (subject to extension to February 1, 2020 if the Company draws the second tranche of $15 million loans under the term loan facility). Commencing on the amortization date, and continuing on the payment date of each month thereafter, the Company is required to make consecutive equal monthly payments of principal of each term loan, together with accrued interest, in arrears, to the Oxford. All unpaid principal, accrued and unpaid interest with respect to each term loan, and a final payment in the amount of 5.0% of the amount of loans advanced, is due and payable in full on the term loan maturity date. The term loan facility has a term of five years and matures on January 1, 2022. At the Company’s option, the Company may prepay all, but not less than all, of the term loans advanced by Oxford under the term loan facility, subject to a prepayment fee and an amount equal to the sum of all outstanding principal of the term loans plus accrued and unpaid interest thereon through the prepayment date, a final payment, plus all other amounts that are due and payable, including Oxford's expenses and interest at the default rate with respect to any past due amounts. The credit facility also includes events of default, the occurrence and continuation of which could cause interest to be charged at the rate that is otherwise applicable plus 5.0% and would provide Oxford, as collateral agent with the right to exercise remedies against us and the collateral securing the credit facility, including foreclosure against assets securing the credit facilities, including the Company’s cash. These events of default include, among other things, the Company’s failure to pay any amounts due under the credit facility, a breach of covenants under the credit facility, the Company’s insolvency, a material adverse change, the occurrence of any default under certain other indebtedness in an amount greater than $500,000 , one or more judgments against us in an amount greater than $500,000 , a material adverse change with respect to any governmental approval and any delisting event. S-3 Shelf Registration On January 9, 2017, the Company filed a shelf registration statement on Form S-3 with the SEC. Upon being declared effective by the SEC, the shelf registration statement will allow the Company to sell from time to time up to $200 million of its common stock, preferred stock, debt securities, warrants, or units comprised of any combination of these securities, for its own account in one or more offerings. The shelf registration statement, once effective, is intended to provide the Company flexibility to conduct registered sales of its securities, subject to market conditions and our future capital needs. There are no guarantees that the SEC will declare the shelf effective or that we will be able to sell any securities pursuant to it. The terms of any offering under the shelf registration statement will be established at the time of such offering and will be described in a prospectus supplement filed with the SEC prior to the completion of any such offering.

Organization and Basis of Pre26

Organization and Basis of Presentation (Policies)	12 Months Ended
	Dec. 31, 2016
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Basis of presentation and use of estimates	Basis of presentation and use of estimates The preparation of consolidated financial statements in conformity with accounting principles generally accepted in the United States requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities and disclosure of contingent assets and liabilities at the date of the consolidated financial statements, and the reported amounts of revenue and expenses during the reporting periods. The most significant estimates used in these consolidated financial statements include the valuation of accounts receivable, inventory reserves, intangible valuation, equity instruments, impairment assessments, income tax reserves and related allowances, and the lives of property and equipment. Actual results may differ from those estimates.

Summary of Significant Accoun27

Summary of Significant Accounting Policies (Policies)	12 Months Ended
	Dec. 31, 2016
Accounting Policies [Abstract]
Concentrations of credit risk and other risks and uncertainties	Concentrations of credit risk and other risks and uncertainties Financial instruments that subject the Company to credit risk primarily consist of cash, cash equivalents and accounts receivable. The Company maintains the majority of its cash with accredited financial institutions. The Company and its contract manufacturers rely on sole source suppliers and service providers for certain components. There can be no assurance that a shortage or stoppage of shipments of the materials or components that the Company purchases will not result in a delay in production or adversely affect the Company’s business. The Company is in the process of validating alternate suppliers relative to certain key components, which are expected to be phased in during the coming periods. For the years ended December 31, 2016 , 2015 and 2014 , no customer represented greater than 10% of revenue. There were no customers that represented greater than 10% of total gross receivable balance at December 31, 2016 , 2015 and 2014 .
Principles of consolidation	Principles of consolidation The consolidated financial statements include the accounts of the Company and its wholly owned subsidiaries including ImaTx, Inc., ConforMIS Europe GmbH, ConforMIS UK Limited and ConforMIS Hong Kong Limited. All material intercompany balances and transactions have been eliminated in consolidation.
Cash and cash equivalents	Cash and cash equivalents The Company considers all highly liquid investment instruments with original maturities of 90 days or less when purchased, to be cash equivalents. The Company’s cash equivalents consist of demand deposits and money market accounts on deposit with certain financial institutions in excess of federally insured limits. Demand deposits are carried at cost which approximates their fair value. Money market accounts are carried at fair value based upon level 1 inputs. See “Note C — Fair Value Measurements” below. The associated risk of concentration is mitigated by banking with credit worthy financial institutions.
Investment securities	Investment securities The Company classifies its investment securities as available-for-sale. Those investments with maturities less than 12 months at the date of purchase are considered short-term investments. Those investments with maturities greater than 12 months at the date of purchase are considered long-term investments. The Company’s investment securities classified as available-for-sale are recorded at fair value based upon quoted market prices at period end. Unrealized gains and losses, deemed temporary in nature, are reported as a separate component of accumulated other comprehensive income (loss). A decline in the fair value of any security below cost that is deemed other than temporary results in a charge to earnings and the corresponding establishment of a new cost basis for the security. Premiums (discounts) are amortized (accreted) over the life of the related security the constant yield method. Dividend and interest income are recognized when earned and reported in other income. Realized gains and losses are included in earnings and are derived using the specific identification method for determining the cost of securities sold.
Fair value of financial instruments	Fair value of financial instruments Certain of the Company’s financial instruments, including cash and cash equivalents, excluding money market funds, accounts receivable, accounts payable, accrued expenses and other liabilities are carried at cost, which approximates their fair value because of the short-term maturity. Based on borrowing rates currently available to the Company for loans with similar terms, the carrying value of the Company’s long-term debt approximates its fair value.
Accounts receivable and allowance for doubtful accounts	Accounts receivable and allowance for doubtful accounts Accounts receivable consist of amounts due from medical facilities that have been billed and unbilled. Upon completion of a procedure, revenue is recognized and unbilled receivable is recorded. Upon receipt of a purchase order number from the medical facility, which is used by the medical facility to facilitate payment, a billed receivable is recorded and the unbilled receivable is reversed. The unbilled receivable balance fluctuates based on the timing of when purchase order numbers are received from medical facilities. In estimating whether accounts receivable can be collected, the Company performs evaluations of customers and continuously monitors collections and payments and estimates an allowance for doubtful accounts based on the aging of the underlying invoices, collections experience to date and any specific collection issues that have been identified. The allowance for doubtful accounts is recorded in the period in which revenue is recorded or when collection risk is identified.
Inventories	Inventories Inventories consist of raw materials, work-in-process components and finished goods. Inventories are stated at the lower of cost, determined using the first-in first-out method, or market value. The Company regularly reviews its inventory quantities on hand and related cost and records a provision for any excess or obsolete inventory based on its estimated forecast of product demand and existing product configurations. The Company also reviews its inventory value to determine if it reflects the lower of cost or market, with market determined based on net realizable value. Appropriate consideration is given to inventory items sold at negative gross margins, purchase commitments and other factors in evaluating net realizable value.
Property and equipment	Property and equipment Property and equipment is stated at cost less accumulated depreciation and is depreciated using the straight-line method over the estimated useful lives of the respective assets. Leasehold improvements are amortized over their useful life or the life of the lease, whichever is shorter. Assets capitalized under capital leases are amortized in accordance with the respective class of assets and the amortization is included with depreciation expense. Maintenance and repair costs are expensed as incurred.
Intangibles and other long-lived assets	Intangibles and other long-lived assets Intangible assets consist of developed technology and other intellectual property rights licensed from ImaTx as part of the spin-out transaction in 2004. Intangible assets are carried at cost less accumulated amortization. The Company tests impairment of long-lived assets when events or changes in circumstances indicate that the assets might be impaired. For assets with determinable useful lives, amortization is computed using the straight-line method over the estimated economic lives of the respective intangible assets. Furthermore, periodically the Company assesses whether long-lived assets, including intangible assets, should be tested for recoverability whenever events or circumstances indicate that their carrying value may not be recoverable. The amount of impairment, if any, is measured based on fair value, which is determined using estimated undiscounted cash flows to be generated from such assets or group of assets. If the cash flow estimates or the significant operating assumptions upon which they are based change in the future, the Company may be required to record impairment charges. During the year ended December 31, 2016 , the Company recognized an impairment of long-term assets of $0.1 million in connection with certain manufacturing equipment previously purchased that was returned to the seller in exchange for credit toward future purchase. The value of such credit is less than the book value of the equipment. During the years ended December 31, 2015 and 2014 , no such impairment charges were recognized.
Goodwill	Goodwill Goodwill relates to amounts that arose in connection with the acquisition of Imaging Therapeutics, Inc. (formerly known as Osteonet.com, renamed ImaTx, Inc.) in 2009. The Company tests goodwill at least annually for impairment, or more frequently when events or changes in circumstances indicate that the assets may be impaired. This impairment test is performed annually during the fourth quarter at the reporting unit level. Goodwill may be considered impaired if the carrying value of the reporting unit, including goodwill, exceeds the reporting unit’s fair value. The Company is comprised of one reporting unit. When testing goodwill for impairment, the Company has the option to first assess the qualitative factors to determine whether it is more likely than not that the fair value of its reporting unit is less than its carrying amount. This qualitative analysis is used as a basis for determining whether it is necessary to perform the two-step goodwill impairment analysis. If the Company determines that it is more likely than not that its fair value is less than its carrying amount, then the two-step goodwill impairment test will be performed. If the two-step approach is performed, the Company will estimate fair value of the reporting unit, which is typically estimated using a discounted cash flow approach, and requires the use of assumptions and judgments including estimates of future cash flows and the selection of discount rates. During the years ended December 31, 2016 , 2015 and 2014 , there were no triggering events which would require the two-step goodwill impairment assessment.
Revenue recognition	Revenue recognition Product The Company generates revenue from the sale of customized implants and instruments to medical facilities through the use of a combination of direct sales personnel, independent sales representatives and distributors in the United States, Germany, the United Kingdom, Ireland, Austria, Switzerland, Singapore and Hong Kong. Revenue is recognized when all of the following criteria are met: • persuasive evidence of an arrangement exists; • the sales price is fixed or determinable; • collection of the relevant receivable is probable at the time of sale; and • delivery has occurred or services have been rendered. For a majority of sales to medical facilities, the Company recognizes revenue upon completion of the procedure, which represents satisfaction of the required revenue recognition criteria. For the remaining sales, which are made directly through distributors and generally represent approximately 1% of revenue, the Company recognizes revenue at the time of shipment of the product, which represents the point in time when the customer has taken ownership and assumed the risk of loss and the required revenue recognition criteria are satisfied. Such customers are obligated to pay within specified time periods regardless of when or if they ever sell or use the products. Once the revenue recognition criteria have been satisfied the Company does not offer rights of return or price protection and there are no post-delivery obligations. Royalty In April 2015, the Company entered into a fully paid up, worldwide license agreement with Wright Medical Group, Inc., or Wright Group, and its wholly owned subsidiary Wright Medical Technology, Inc., or Wright Technology and collectively with Wright Group, Wright Medical. Under the terms of this license agreement, the Company granted a perpetual, irrevocable, non-exclusive license to Wright Medical to use patient-specific instrument technology covered by the Company’s patents and patent applications with off-the-shelf implants in the foot and ankle. This license does not extend to patient-specific implants. This license agreement provided for a single lump-sum payment by Wright Medical to the Company upon entering into the license agreement, which has been paid. This license agreement will expire upon the expiration of the last to expire of the Company’s patents and patent applications licensed to Wright Medical, which currently is expected to occur in 2031. In April 2015, the Company entered into a worldwide license agreement with MicroPort Orthopedics Inc., or MicroPort, a wholly owned subsidiary of MicroPort Scientific Corporation. Under the terms of this license agreement, the Company granted a perpetual, irrevocable, non-exclusive license to MicroPort to use patient-specific instrument technology covered by the Company’s patents and patent applications with off-the-shelf implants in the knee. This license does not extend to patient-specific implants. This license agreement provides for the payment to the Company of a fixed royalty percentage of net sales on patient-specific instruments and associated implant components in the knee, including MicroPort’s Prophecy patient-specific instruments used with its Advance and Evolution implant components. This license agreement also provided for a single lump-sum payment by MicroPort to the Company upon entering into the license agreement, which has been paid. This license agreement will expire upon the expiration of the last to expire of the Company’s patents and patent applications licensed to MicroPort, which currently is expected to occur in 2029. The Company has accounted for the agreements with Wright Medical and MicroPort under ASC 605-25, Multiple-Element Arrangements and Staff Accounting Bulletin No. 104, Revenue Recognition (ASC 605). In accordance with ASC 605, the Company is required to identify and account for each of the separate units of accounting. The Company identified the relative selling price for each and then allocated the total consideration based on their relative values. In connection with these agreements, in April 2015, the Company recognized in aggregate (i) back-owed royalties of $3.4 million as royalty revenue and (ii) the value attributable to the settlements of $0.2 million as other income. Additionally, the Company recognized an initial $5.1 million in aggregate as deferred royalty revenue, which is recognized as royalty revenue ratably through 2031. See “Note I — Deferred Revenue”. The on-going royalty from MicroPort is recognized as royalty revenue upon receipt of payment.
Shipping and handling costs	Shipping and handling costs Amounts invoiced to customers for shipping and handling are classified as revenue. Shipping and handling costs incurred are included in general and administrative expense. Shipping and handling expense was $1.6 million , $2.7 million and $1.4 million for the years ended December 31, 2016 , 2015 and 2014 , respectively.
Taxes collected from customers and remitted to government authorities	Taxes collected from customers and remitted to government authorities The Company’s policy is to present taxes collected from customers and remitted to government authorities on a net basis and not to include tax amounts in revenue.
Research and development expense	Research and development expense The Company’s research and development costs consist of engineering, product development, quality assurance, clinical and regulatory expense. These costs primarily relate to employee compensation, including salary, benefits and stock-based compensation. The Company also incurs costs related to consulting fees, materials and supplies, and marketing studies, including data management and associated travel expense. Research and development costs are expensed as incurred.
Advertising expense	Advertising expense Advertising costs are expensed as incurred, which are included in sales and marketing. Advertising expense was $0.3 million for the year ended December 31, 2016 , $0.3 million for the year ended December 31, 2015 and $0.5 million for the year ended December 31, 2014 .
Segment reporting	Segment reporting Operating segments are defined as components of an enterprise about which separate financial information is available and is evaluated on a regular basis by the chief operating decision-maker, or decision-making group, in deciding how to allocate resources to an individual segment and in assessing performance of the segment. The Company’s chief operating decision-maker is its chief executive officer. The Company’s chief executive officer reviews financial information presented on an aggregate basis for purposes of allocating resources and evaluating financial performance. The Company has one business activity and there are no segment managers who are held accountable for operations, operating results and plans for products or components below the aggregate Company level. Accordingly, in light of the Company’s current product offerings, management has determined that the primary form of internal reporting is aligned with the offering of the ConforMIS customized joint replacement products and that the Company operates as one segment. See “Note O——Segment and Geographic Data”.
Comprehensive loss	Comprehensive loss At December 31, 2016 , 2015 and 2014 , accumulated other comprehensive loss consists of foreign currency translation adjustments and changes in unrealized gain and loss of available-for-sale securities, net of tax.
Foreign currency translation and transactions	Foreign currency translation and transactions The assets and liabilities of the Company’s foreign operations are translated into U.S. dollars at current exchange rates at the balance sheet date, and income and expense items are translated at average rates of exchange prevailing during the year. Gains and losses realized from transactions denominated in foreign currencies, including intercompany balances not considered permanent investments, are included in the consolidated statements of operations.
Income taxes	Income taxes Income taxes are accounted for under the asset and liability method. Deferred tax assets and liabilities are recognized for the future tax consequences attributable to differences between the consolidated financial statement carrying amounts of existing assets and liabilities and their respective tax bases, operating losses and tax credit carry forwards. Deferred tax assets and liabilities are measured using enacted tax rates expected to apply to taxable income in the years in which those temporary differences are expected to be recovered or settled. The effect on deferred tax assets and liabilities of a change in tax rates is recognized as income in the period that includes the enactment date. The tax benefit from an uncertain tax position is only recognized if it is more likely than not that the tax position will be sustained on examination by the taxing authorities, based on the technical merits of the position. The tax benefits recognized in the consolidated financial statements from these positions are measured based on the largest benefit that has a greater than fifty percent likelihood of being realized upon ultimate resolution. The Company reviews its tax positions on an annual basis and more frequently as facts surrounding tax positions change. Based on these future events, the Company may recognize uncertain tax positions or reverse current uncertain tax positions, the impact of which would affect the consolidated financial statements.
Medical device excise tax	Medical device excise tax The Company is subject to the Health Care and Education Reconciliation Act of 2010 (the “Act”), which imposes a tax equal to 2.3% on the sales price of any taxable medical device by a medical device manufacturer, producer or importer of such device. Under the Act, a taxable medical device is any device defined in section 201(h) of the Federal Food, Drug, and Cosmetic Act, intended for humans, which includes an instrument, apparatus, implement, machine, contrivance, implant, in vitro reagent, or other similar or related article, including any component, part, or accessory, which meets certain requirements. The Consolidated Appropriations Act of 2016 includes a two-year moratorium on the medical device excise tax, which moratorium suspended taxes on the sale of a taxable medical device by the manufacturer, producer, or importer of the device during the period beginning on January 1, 2016 and ending on December 31, 2017. As such, the Company did not incur medical device excise tax expense for the year ended December 31, 2016 . The Company incurred medical device excise tax expense of $0.8 million for the year ended December 31, 2015 and $0.7 million for the year ended December 31, 2014 , respectively. Medical device tax is included in general and administrative expense.
Stock-based compensation	Stock-based compensation The Company accounts for stock-based compensation in accordance with ASC 718, Stock Based Compensation. ASC 718 requires all stock-based payments to employees and consultants, including grants of stock options, to be recognized in the consolidated statements of operations based on their fair values. The Company uses the Black-Scholes option pricing model to determine the weighted-average fair value of options granted and recognizes the compensation expense of stock-based awards on a straight-line basis over the vesting period of the award. The determination of the fair value of stock-based payment awards utilizing the Black-Scholes option pricing model is affected by the stock price, exercise price, and a number of assumptions, including expected volatility of the stock, expected life of the option, risk-free interest rate and expected dividends on the stock. The Company evaluates the assumptions used to value the awards at each grant date and if factors change and different assumptions are utilized, stock-based compensation expense may differ significantly from what has been recorded in the past. If there are any modifications or cancellations of the underlying unvested securities, the Company may be required to accelerate, increase or cancel any remaining unearned stock-based compensation expense. The stock price for option grants are set by the Company’s board of directors and, prior to the Company’s IPO in July 2015, were based upon guidance set forth by the American Institute of Certified Public Accountants, or AICPA, in its Technical Practice Aid, “Valuation of Privately Held Company Equity Securities Issued as Compensation”. To that end, the board considered a number of factors in determining the option price, including: (1) past sales of the Company’s convertible preferred stock, and the rights, preferences and privileges of the Company stock, (2) obtaining FDA 510(k) clearance, and (3) achievement of budgeted results. See “Note M——Stockholders’ Equity” for a summary of the stock option activity under the Company’s stock-based compensation plan.
Net loss per share	Net loss per share The Company calculates net loss per share in accordance with Accounting Standards Codification 260, Earnings per Share. Basic earnings per share (“EPS”) is calculated by dividing the net income or loss for the period by the weighted average number of common shares outstanding for the period, without consideration for common stock equivalents. Diluted EPS is computed by dividing the net income or loss for the period by the weighted average number of common shares outstanding for the period and the weighted average number of dilutive common stock equivalents outstanding for the period determined using the treasury stock method.
Recent accounting pronouncements	Recent accounting pronouncements In November 2016, the Financial Accounting Standards Board ("FASB") issued Accounting Standard Update ("ASU') No. 2016-18, “Statement of Cash Flows (Topic 230) Restricted Cash a consensus of the FASB Emerging Issues Task Force” (“ASU 2016-18”). The standard requires restricted cash and cash equivalents to be included with cash and cash equivalents on the statement cash flows. The guidance will be effective in the first quarter of 2018, with early adoption permitted. The Company is currently evaluating the impact of this pronouncement on its consolidated financial statements and expects to adopt this pronouncement commencing in the first quarter of 2018. In June 2016, the FASB issued ASU No. 2016-12, "Revenue from Contracts with Customers (Topic 606): Narrow-Scope Improvements and Practical Expedients" ("ASU 2016-12") which provides guidance for accounting of credit losses affecting the impairment model for most financial assets and certain other instruments. Entities will be required to use a new forward-looking current expected credit loss model for trade and other receivables, held-to-maturity debt securities, loans and other instruments, which will generally lead to an earlier recognition of loss allowances. Entities will recognize losses on available-for-sale debt securities as allowances rather than a reduction in amortized cost of the security while the measurement process of this loss does not change. Disclosure requirements are expanded regarding an entity’s assumptions, models and methods of estimations of the allowance. The guidance will be effective in the first quarter of 2018, with the option for early adoption. The Company is currently evaluating the impact of this pronouncement on its consolidated financial statements and expects to adopt this pronouncement commencing in the first quarter of 2018. In April 2016, the FASB issued ASU 2016-10, "Identifying Performance Obligations and Licensing" ("ASU 2016-10"). This ASU clarifies two aspects of ASU 2014-09, "Revenue from Contracts with Customers (Topic 606): identifying performance obligations and the licensing implementation guidance". ASU 2016-10 will become effective for the first quarter of 2018. The Company is currently evaluating the impact of this pronouncement on its consolidated financial statements and expects to adopt this pronouncement commencing in the first quarter of 2018. In March 2016, the FASB issued ASU 2016-09, "Compensation - Stock Compensation" ("ASU 2016-09"). This ASU revises the accounting for share-based payment transactions, including the income tax consequences, classification of awards as either equity or liabilities, and an option to recognized gross stock compensation expense with actual forfeitures recognized as they occur, as well as certain classifications on the statement of cash flows. This ASU is effective for annual reporting periods beginning after December 15, 2016, including interim reporting periods within that reporting year, and early adoption is permitted. The Company will adopt this pronouncement commencing in the first quarter of 2017. The Company will apply ASU 2016-09 using a modified retrospective approach and adopt the option to recognize gross stock compensation expense with actual forfeitures recognized as they occur, with the cumulative-effect adjustment to retained earnings, which the Company does not anticipate will have a material impact on its consolidated financial statements. In March 2016, the FASB issued ASU No. 2016-08, "Revenue from Contracts with Customers (Topic 606): Principal versus Agent Considerations (Reporting Revenue Gross versus Net)" ("ASU 2016-08") which clarifies the implementation guidance on principal versus agent considerations. The guidance includes indicators to assist an entity in determining whether it controls a specified good or service before it is transferred to the customers. This guidance will be effective in the first quarter of 2018, with the option to adopt it in the first quarter of 2017. The Company does not anticipate the pronouncement will have a material impact on its consolidated financial statements and expects to adopt this pronouncement commencing in the first quarter of 2018. In February 2016, the FASB issued ASU No. 2016-02, "Leases (Topic 842)." This ASU is a comprehensive new leases standard that amends various aspects of existing guidance for leases and requires additional disclosures about leasing arrangements. It will require companies to recognize lease assets and lease liabilities by lessees for those leases classified as operating leases under previous GAAP. Topic 842 retains a distinction between finance leases and operating leases. The classification criteria for distinguishing between finance leases and operating leases are substantially similar to the classification criteria for distinguishing between capital leases and operating leases in the previous leases guidance. The ASU is effective for annual periods beginning after December 15, 2018, including interim periods within those fiscal years; earlier adoption is permitted. In the financial statements in which the ASU is first applied, leases shall be measured and recognized at the beginning of the earliest comparative period presented with an adjustment to equity. Practical expedients are available for election as a package and if applied consistently to all leases. The Company is currently evaluating the impact of this pronouncement on its consolidated financial statements and expect to adopt this pronouncement commencing in the first quarter of 2019. In November 2015, the FASB issued ASU No. 2015-17, "'Income Taxes (Topic 740): Balance Sheet Classification of Deferred Taxes" ("ASU 2015-17"), which eliminates the current requirement for organizations to present deferred tax liabilities and assets as current and noncurrent in a classified balance sheet. Instead, organizations will be required to classify all deferred tax assets and liabilities as noncurrent. This guidance is effective for public companies financial statements issued for annual periods beginning after December 15, 2016, and interim periods within those annual periods. We do not expect that the adoption of ASU 2015-17 will have a material effect on our consolidated financial statements and will adopt this pronouncement commencing in the first quarter of 2017. In May 2014, the FASB issued ASU No. 2014-9, “Revenue from Contracts with Customers (Topic 606)” ("ASU 2014-9"). ASU 2014-9 outlines a single comprehensive model for entities to use in accounting for revenue arising from contracts with customers and supersedes most current revenue recognition guidance, including industry-specific guidance. This new guidance was to be effective for annual reporting periods (including interim reporting periods within those periods) beginning after December 15, 2017; early adoption was permitted for annual reporting periods beginning after December 15, 2016, including interim reporting periods within those annual periods. Companies have the option of using either a full retrospective or a modified retrospective approach to adopt the guidance. In August 2015, the FASB issued ASU 2015-14 to defer the effective date of the guidance contained in ASU 2014-9 by one year. Thus, the guidance is effective for us commencing in the first quarter of 2018. The Company is currently assessing the impact of this guidance on its results of operations and related disclosures. Based on the procedures performed to date, nothing has come to its attention that would indicate that the adoption of ASU 2014-09 will have a material impact on its accounting for revenue arising from contracts with customers, but will require additional disclosure in its financial statements, however, the Company expects to complete this assessment in 2017. The Company expects to adopt this pronouncement and related disclosures commencing in the first quarter of 2018.
Reclassification	Reclassification During 2016, the Company identified that certain costs of revenue related to unused product in connection with known and potential cancelled cases had been improperly classified as sales and marketing expense. The Company concluded that the prior classification was an error and that it is immaterial to all annual and quarterly periods previously presented. To facilitate period-over-period comparisons, the Company revised its prior period financial statements to reflect the corrections in the period in which the expenses were incurred.

Summary of Significant Accoun28

Summary of Significant Accounting Policies (Tables)	12 Months Ended
	Dec. 31, 2016
Accounting Policies [Abstract]
Schedule of accumulated other comprehensive income (loss)	The following table summarizes accumulated beginning and ending balances for each item in Accumulated other comprehensive income (loss). Foreign currency translation adjustments Change in unrealized gain (loss) on available-for-sale securities, net of tax Accumulated other comprehensive income (loss) Balance December 31, 2015 $ (521 ) $ — $ (521 ) Change in period 1,027 (7 ) 1,020 Balance December 31, 2016 $ 506 $ (7 ) $ 499
Schedule of computation of basic and diluted earnings per share attributable to stockholders	The following table sets forth the computation of basic and diluted earnings per share attributable to stockholders (in thousands, except share and per share data): Years Ended December 31, (in thousands, except share and per share data) 2016 2015 2014 Numerator: Numerator for basic and diluted loss per share: Net loss $ (57,588 ) $ (57,246 ) $ (45,722 ) Denominator: Denominator for basic loss per share: Weighted average shares 41,521,629 21,993,066 4,239,564 Basic loss per share attributable to ConforMIS, Inc. stockholders $ (1.39 ) $ (2.60 ) $ (10.78 ) Diluted loss per share attributable to ConforMIS, Inc. stockholders $ (1.39 ) $ (2.60 ) $ (10.78 )
Schedule of potential shares of common stock equivalents that are antidilutive and not included in the calculation of diluted net loss per share	The following table sets forth potential shares of common stock equivalents that are not included in the calculation of diluted net loss per share because to do so would be anti-dilutive as of the end of each period presented: Years Ended December 31, 2016 2015 2014 Series A Preferred — 873,591 1,705,138 Series B Preferred — 1,144,885 2,234,668 Series C Preferred — 1,256,752 2,453,018 Series D Preferred — 3,410,570 6,415,106 Series E-1 Preferred — 3,748,578 6,530,429 Series E-2 Preferred — 2,628,037 5,129,592 Series C Preferred Warrants — — 56,202 Series D Preferred Warrants — — 58,365 Series E-2 Preferred Warrants — — 5,883 Common stock warrants 34,709 303,931 25,733 Stock options 1,959,030 3,566,421 2,780,631 Total 1,993,739 16,932,765 27,394,765

Fair Value Measurements (Tables

Fair Value Measurements (Tables)	12 Months Ended
	Dec. 31, 2016
Fair Value Disclosures [Abstract]
Schedule of Fair Value, Assets and Liabilities Measured on Recurring Basis	The following table summarizes, by major security type, the Company's assets that are measured at fair value on a recurring basis and are categorized using the fair value hierarchy and where they are classified on the Consolidated Balance Sheets (in thousands): December 31, 2016 Amortized Cost Gross Unrealized Gains Gross Unrealized Losses Estimated Fair Value Cash and cash equivalents Short-term (1) investments Cash $ 8,504 $ — $ — $ 8,504 $ 8,504 $ — Level 1 securities: Money market funds 28,753 — — 28,753 28,753 — Level 2 securities: Corporate bonds 6,701 — (4 ) 6,697 — 6,697 Agency bond $ 21,548 $ — $ (3 ) $ 21,545 $ — $ 21,545 Total $ 65,506 $ — $ (7 ) $ 65,499 $ 37,257 $ 28,242 December 31, 2015 Amortized Cost Gross Unrealized Gains Gross Unrealized Losses Estimated Fair Value Cash and cash equivalents Short-term (1) investments Cash $ 10,302 $ — $ — $ 10,302 $ 10,302 $ — Level 1 securities: Money market funds 106,883 — — 106,883 106,883 — Total $ 117,185 $ — $ — $ 117,185 $ 117,185 $ — (1) Contractual maturity due within one year.

Accounts Receivable (Tables)

Accounts Receivable (Tables)	12 Months Ended
	Dec. 31, 2016
Accounts Receivable, Net, Current [Abstract]
Schedule of accounts receivable	Accounts receivable consisted of the following (in thousands): December 31, December 31, Total receivables $ 15,356 $ 15,421 Allowance for doubtful accounts and returns (681 ) (554 ) Accounts receivable, net $ 14,675 $ 14,867
Allowance for doubtful accounts receivable	Summary of allowance for doubtful accounts and returns activity was as follows (in thousands): December 31, 2016 December 31, 2015 Beginning balance $ (554 ) $ (162 ) Provision for bad debts on trade receivables (188 ) (359 ) Other allowances 20 (121 ) Accounts receivable write offs 41 88 Ending balance $ (681 ) $ (554 )

Inventories (Tables)

Inventories (Tables)	12 Months Ended
	Dec. 31, 2016
Inventory Disclosure [Abstract]
Schedule of inventories	Inventories consisted of the following (in thousands): December 31, December 31, Raw Material $ 3,331 $ 4,175 Work in process 2,530 2,683 Finished goods 5,859 4,662 Total Inventories $ 11,720 $ 11,520

Property and Equipment (Tables)

Property and Equipment (Tables)	12 Months Ended
	Dec. 31, 2016
Property, Plant and Equipment [Abstract]
Schedule of property and equipment	Property and equipment consisted of the following (in thousands): Estimated Useful Life (Years) December 31, December 31, Equipment 5-7 $ 16,651 $ 12,185 Furniture and fixtures 5-7 414 391 Computer and software 3 7,027 5,229 Leasehold improvements 2-7 1,294 795 Total property and equipment 25,386 18,600 Accumulated depreciation (10,302 ) (7,634 ) Property and equipment, net $ 15,084 $ 10,966

Intangible Assets (Tables)

Intangible Assets (Tables)	12 Months Ended
	Dec. 31, 2016
Intangible Assets, Net (Excluding Goodwill) [Abstract]
Components of intangible assets	The components of intangible assets consisted of the following (in thousands): Estimated Useful Life (Years) December 31, 2016 December 31, 2015 Developed technology 10 $ 979 $ 979 Accumulated amortization (681 ) (582 ) Developed technology, net 298 397 License agreements 10 1,508 1,508 Accumulated amortization (1,060 ) (910 ) License technology, net 448 598 Intangible assets, net 10 $ 746 $ 995
Schedule of estimated future aggregated amortization expense	The estimated future aggregated amortization expense for intangible assets owned as of December 31, 2016 consisted of the following (in thousands): Amortization expense 2017 $ 249 2018 249 2019 248 $ 746

Accrued Expenses (Tables)

Accrued Expenses (Tables)	12 Months Ended
	Dec. 31, 2016
Accrued Liabilities and Other Liabilities [Abstract]
Schedule of accrued expenses	Accrued expenses consisted of the following (in thousands): December 31, December 31, Accrued employee compensation $ 4,037 $ 3,585 Deferred rent 101 213 Accrued legal expense 710 334 Accrued consulting expense 104 134 Accrued vendor charges 1,396 692 Accrued revenue share expense 992 932 Accrued patent settlement and license costs — 500 Accrued clinical trial expense 256 302 Accrued other 896 1,119 $ 8,492 $ 7,811

Commitments and Contingencies (

Commitments and Contingencies (Tables)	12 Months Ended
	Dec. 31, 2016
Commitments and Contingencies Disclosure [Abstract]
Schedule of future minimum rental payments under the entity's non-cancellable operating leases	The future minimum rental payments under the Company’s non-cancellable operating leases for real estate as of December 31, 2016 were as follows (in thousands): Year Minimum lease Payments 2017 $ 1,179 2018 1,500 2019 1,537 2020 1,574 2021 1,611 2022-2025 4,323 $ 11,724
Contractual obligation, fiscal year maturity schedule	The following table summarizes the Company's contractual obligations as of the year ended December 31, 2016 (in thousands): Payment Due by Period Contractual Obligations Total Less than 1 year Years 1 to 3 Years 3 to 5 After 5 years Operating lease obligations - real estate (1) 11,724 1,179 3,037 3,185 4,323 Other (2) 1,418 484 409 400 125 Total (3) $ 13,142 $ 1,663 $ 3,446 $ 3,585 $ 4,448 (1) Represents operating lease commitments for office and manufacturing space in Bedford, Wilmington and Billerica, Massachusetts. (2) Represents amounts payable under our product royalty agreements, operating leases for office equipment and a software development collaboration project (3) This table does not include: (a) revenue share obligations to past and present members of our scientific advisory board and one of our directors, as the amounts of such payments are not known with certainty; and (b) contracts that are entered into in the ordinary course of business that are not material in the aggregate in any period presented above. See "—Revenue share agreements" and "Certain Relationships and Related-Persons Transactions—Revenue share agreement with Dr. Lang" for a description of our revenue share arrangements.

Stockholders' Equity (Tables)

Stockholders' Equity (Tables)	12 Months Ended
	Dec. 31, 2016
Schedule of common stock activity	Summary of common stock activity was as follows: Shares Outstanding December 31, 2014 4,286,164 Issuance of common stock - option & warrant exercises 395,192 Issuance of restricted common stock 174,530 Issuance of common stock - IPO 10,350,000 Issuance of common stock - preferred stock conversion to common stock 25,904,241 Outstanding December 31, 2015 41,110,127 Issuance of common stock - option & warrant exercises 1,485,401 Issuance of restricted common stock 804,019 Outstanding December 31, 2016 43,399,547
Schedule of activity under all stock option plans	Activity under all stock option plans was as follows: Number of Options Weighted Average Exercise Price per Share Aggregate Intrinsic Value (In Thousands) Outstanding December 31, 2013 4,869,330 $ 3.77 Granted 1,037,547 9.77 Exercised (118,738 ) 1.50 Expired (142,206 ) 5.29 Cancelled/Forfeited (290,366 ) 5.08 Outstanding December 31, 2014 5,355,567 $ 4.87 Granted 403,086 12.20 Exercised (383,458 ) 2.10 Expired (30,876 ) 5.97 Cancelled/Forfeited (95,990 ) 7.42 Outstanding December 31, 2015 5,248,329 $ 5.56 Granted 179,178 8.78 Exercised (1,467,692 ) 2.78 8,219 Expired (81,251 ) 9.70 Cancelled/Forfeited (88,524 ) 9.93 Outstanding December 31, 2016 3,790,040 $ 6.60 $ 8,547 Total vested and exercisable 3,231,167 $ 6.01 $ 8,514
Schedule of restricted common stock award activity	Restricted common stock award activity under the plan was as follows: Number of Shares Weighted Average Fair Value Unvested December 31, 2014 — $ — Granted 174,530 22.31 Unvested December 31, 2015 174,530 $ 22.31 Granted 873,589 8.61 Vested (66,839 ) 17.72 Forfeited (69,570 ) 11.83 Unvested December 31, 2016 911,710 $ 10.32
Assumptions used to estimate the fair value of options at date of grant	The fair value of options at date of grant was estimated using the Black-Scholes option pricing model, based on the following assumptions: Years Ended December 31, 2016 2015 2014 Risk-free interest rate 1.98% 1.37% - 1.77% 1.66% - 2.29% Expected term (in years) 6.25 5.47 - 6.45 5.00 - 7.25 Dividend yield —% —% —% Expected volatility 51.00% 49.00% - 50.00% 50.00%
Summary of stock-based compensation expense	The following is a summary of stock-based compensation expense (in thousands): Years Ended December 31, 2016 2015 2014 Cost of revenues $ 333 $ 239 $ 162 Sales and marketing 1,197 730 597 Research and development 1,466 784 628 General and administrative 2,328 1,854 1,163 $ 5,324 $ 3,607 $ 2,550
Common stock warrants
Assumptions used to estimate the fair value of warrants at date of grant	The fair value of warrants at date of grant was estimated using the Black-Scholes option pricing model, based on the following assumptions in the year ended December 31, 2014: Risk-free interest rate 0.91%-1.71% Expected term (in years) 2.50-5.00 Dividend yield —% Expected volatility 50.00%-55.00%
Summary of stock warrant activity	Summary of common stock warrant activity was as follows: Number of Warrants Weighted Average Exercise Price Per Share Number of Warrants Exercisable Weighted Average Price Per Share Weighted Average Contractual Life Outstanding December 31, 2014 204,312 $ 8.90 204,312 $ 8.90 3.26 Exercised (16,721 ) 7.80 (16,721 ) 7.80 — Converted from preferred warrant 564,188 10.73 564,188 10.73 — Outstanding December 31, 2015 751,779 $ 10.30 751,779 $ 10.30 1.33 Exercised (166,665 ) 9.00 (166,665 ) 9.00 — Cancelled/expired (413,331 ) — (413,331 ) — — Outstanding December 31, 2016 171,783 $ 7.47 171,783 $ 7.47 1.62

Income Taxes (Tables)

Income Taxes (Tables)	12 Months Ended
	Dec. 31, 2016
Income Tax Disclosure [Abstract]
Schedule of income before income tax, domestic and foreign	For financial reporting purposes, income (loss) before income taxes for the years ended December 31, 2016 , 2015 and 2014 include the following components (in thousands): Years ended December 31, 2016 2015 2014 Income (loss) from continuing operations before income taxes: U.S. $ (51,576 ) $ (50,155 ) $ (40,328 ) Non‑U.S. (5,949 ) (7,050 ) (5,353 ) $ (57,525 ) $ (57,205 ) $ (45,681 )
Schedule of components of income tax expense (benefit)	Significant components of the provision for income taxes for the years ended December 31, 2016 , 2015 and 2014 were as follows (in thousands): Years ended December 31, 2016 2015 2014 Current: Federal $ — $ — $ — State — — — Foreign 63 41 41 63 41 41 Deferred: Federal — — — State — — — Foreign — — — Total $ 63 $ 41 $ 41
Schedule of effective income tax rate reconciliation	A reconciliation of the income tax expense (benefit) at the statutory federal income tax rate as reflected in the financial statements was as follows: Years ended December 31, 2016 2015 2014 Tax at U.S. statutory rate (34.00 )% (34.00 )% (34.00 )% State taxes, net of federal benefits (2.70 ) (2.27 ) (2.36 ) Permanent items 0.42 1.52 1.46 Tax credit (1.06 ) (0.85 ) (8.59 ) Change in valuation allowance 33.95 31.07 37.49 Foreign rate differential 1.04 1.68 0.68 Rate change (0.06 ) 0.01 (0.02 ) Uncertain tax positions 2.06 2.21 2.97 Other 0.46 0.7 2.47 0.11 % 0.07 % 0.10 %
Schedule of deferred tax assets and liabilities	Significant components of the Company’s deferred tax assets (liabilities) consisted of the following (in thousands): Years ended December 31, 2016 2015 Deferred tax assets: Federal and state net operating loss carryforwards $ 115,719 $ 99,823 Foreign net operating loss carryforwards 2,561 2,973 Accrued expenses 280 — Credits 5,091 4,483 Deferred revenue 1,709 — Other 5,703 4,138 Total deferred tax assets 131,063 111,417 Valuation allowance (130,005 ) (110,518 ) Net deferred tax assets 1,058 899 Deferred tax liabilities: Fixed assets (841 ) (612 ) Intangibles (217 ) (287 ) Other — — Net deferred tax liabilities (1,058 ) (899 ) Net deferred tax assets $ — $ — Current net deferred tax asset 33 15 Long‑term net deferred tax liability (33 ) (15 ) Net deferred tax asset $ — $ —
Schedule of unrecognized tax benefits	Unrecognized tax benefits during the three years ended December 31, 2016 , 2015 and 2014 consisted of the following: Years ended December 31, 2016 2015 2014 Unrecognized tax benefits beginning of year $ 3,730 $ 2,466 $ 1,109 Gross change for current year positions 1,187 1,264 1,357 Decrease for prior period positions — — — Decrease due to settlements and payments — — — Decrease due to statute limitations — — — Unrecognized tax benefits end of the year $ 4,917 $ 3,730 $ 2,466

Segment and Geographic Data (Ta

Segment and Geographic Data (Tables)	12 Months Ended
	Dec. 31, 2016
Segment Reporting [Abstract]
Schedule of revenue by geographic information	Geographic information consisted of the following (in thousands): Years Ended December 31, 2016 2015 2014 Product Revenue United States $ 62,366 $ 47,223 $ 34,350 Germany 14,701 13,795 12,549 Rest of World 1,854 1,773 1,287 $ 78,921 $ 62,791 $ 48,186
Schedule of property, plant and equipment by geographic information	December 31, 2016 2015 Property and equipment, net United States $ 14,971 $ 10,836 Rest of World 113 130 $ 15,084 $ 10,966

Selected Quarterly Financial 39

Selected Quarterly Financial Information (Unaudited) (Tables)	12 Months Ended
	Dec. 31, 2016
Quarterly Financial Information Disclosure [Abstract]
Schedule of Quarterly Financial Information	Three Months Ended December 31, 2016 September 30, 2016 June 30, 2016 March 31, 2016 Total revenue $ 21,673 $ 18,643 $ 19,333 $ 20,250 Gross profit 8,045 5,998 6,001 6,663 Net loss (15,705 ) (12,762 ) (14,052 ) (15,034 ) Net loss per share - basic and diluted $ (0.37 ) $ (0.31 ) $ (0.34 ) $ (0.37 ) Three Months Ended December 31, 2015 September 30, 2015 June 30, 2015 March 31, 2015 Total revenue $ 19,071 $ 13,894 $ 19,222 $ 14,700 Gross profit 6,340 2,762 7,827 4,856 Net loss (14,990 ) (17,107 ) (10,892 ) (14,257 ) Net loss per share - basic and diluted $ (0.37 ) $ (0.45 ) $ (2.51 ) $ (3.32 )

Organization and Basis of Pre40

Organization and Basis of Presentation (Details) - USD ($) $ in Thousands	Dec. 31, 2016	Dec. 31, 2015
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Accumulated deficit	$ (382,930)	$ (325,342)
Cash and cash equivalents and investments	65,500	117,200
Restricted cash	$ 300	$ 600

Organization and Basis of Pre41

Organization and Basis of Presentation (Details 2)	Jan. 09, 2017USD ($)	Jan. 06, 2017USD ($)	Jan. 31, 2017USD ($)loan	Dec. 31, 2016USD ($)
2014 Secured Loan Agreement | Term loan | SVB/Oxford Term Loan B
Liquidity and operations
Maximum amount committed by the lenders under the loan and security agreement				$ 10,000,000
Subsequent Event
Liquidity and operations
Amount of equity able to raise	$ 200,000,000		$ 200,000,000
Subsequent Event | 2017 Secured Loan Agreement | Term loan
Liquidity and operations
Maximum amount committed by the lenders under the loan and security agreement		$ 50,000,000
Number of loans | loan			3
Subsequent Event | 2017 Secured Loan Agreement | Term loan | Oxford Term Loan
Liquidity and operations
Maximum amount committed by the lenders under the loan and security agreement			$ 15,000,000
Amount drawn down		15,000,000	15,000,000
Subsequent Event | 2017 Secured Loan Agreement | Term loan | Oxford Term Loan B
Liquidity and operations
Maximum amount committed by the lenders under the loan and security agreement		15,000,000	15,000,000
Subsequent Event | 2017 Secured Loan Agreement | Term loan | Oxford Term Loan C
Liquidity and operations
Maximum amount committed by the lenders under the loan and security agreement		$ 20,000,000	$ 20,000,000

Organization and Basis of Pre42

Organization and Basis of Presentation (Details 3) - $ / shares	3 Months Ended	12 Months Ended
	Mar. 31, 2015	Dec. 31, 2016	Dec. 31, 2015	Jul. 07, 2015
Class of Stock [Line Items]
Issuance of common stock - IPO			10,350,000
Common stock shares authorized		200,000,000	200,000,000
Preferred stock shares authorized		5,000,000	5,000,000	5,000,000
Expiration of warrants to purchase capital stock (in shares)		413,331
Common stock warrants
Class of Stock [Line Items]
Common stock warrants issued in replacement of preferred stock warrants (in shares)	564,188		564,188
Exercise price of common stock warrants issued in replacement of preferred stock warrants (in dollars per share)			$ 10.73
Common Stock
Class of Stock [Line Items]
Issuance of common stock - IPO			10,350,000

Summary of Significant Accoun43

Summary of Significant Accounting Policies (Concentration RIsk) (Details) - customer	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Credit Concentration Risk
Concentration Risk [Line Items]
Concentration risk, number of customers	0	0	0
Customer Concentration Risk
Concentration Risk [Line Items]
Concentration risk, number of customers	0	0	0

Summary of Significant Accoun44

Summary of Significant Accounting Policies (Cash and Cash Equivalents and Asset Impairment Charges) (Details)	12 Months Ended
	Dec. 31, 2016USD ($)segment	Dec. 31, 2015USD ($)	Dec. 31, 2014USD ($)
Accounting Policies [Abstract]
Cash held in foreign bank accounts	$ 1,600,000	$ 2,100,000
Restricted cash	300,000	600,000
Asset Impairment Charges [Abstract]
Impairment of long term assets	$ 123,000	$ 0	$ 0
Number of reporting units for goodwill testing | segment	1

Summary of Significant Accoun45

Summary of Significant Accounting Policies (Revenue Recognition) (Details) - USD ($) $ in Thousands	1 Months Ended	12 Months Ended
	Apr. 30, 2015	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Revenue recognition
Maximum sales made through distributors, as a percent of revenue (less than)		1.00%
Back-owed royalties recognized as royalty revenue		$ 978	$ 4,096	$ 0
Shipping and handling costs
Shipping and handling expenses		$ 1,600	$ 2,700	$ 1,400
Worldwide license agreement | Wright Medical and MicroPort
Revenue recognition
Back-owed royalties recognized as royalty revenue	$ 3,400
Deferred royalty revenue	5,100
Worldwide license agreement | Wright Medical and MicroPort | Other income
Revenue recognition
Value attributable to the settlements	$ 200

Summary of Significant Accoun46

Summary of Significant Accounting Policies (Expenses and Net Loss Per Share) (Details)	3 Months Ended								12 Months Ended
	Dec. 31, 2016USD ($)	Sep. 30, 2016USD ($)	Jun. 30, 2016USD ($)	Mar. 31, 2016USD ($)	Dec. 31, 2015USD ($)	Sep. 30, 2015USD ($)	Jun. 30, 2015USD ($)	Mar. 31, 2015USD ($)	Dec. 31, 2016USD ($)segment$ / sharesshares	Dec. 31, 2015USD ($)$ / sharesshares	Dec. 31, 2014USD ($)$ / sharesshares
Advertising expense
Advertising expense									$ 300,000	$ 300,000	$ 500,000
Segment reporting
Number of operating segments | segment									1
Medical device excise tax
Excise tax on sales (as a percent)									2.30%
Medical device excise tax expense									$ 0	800,000	700,000
Numerator for basic and diluted loss per share:
Net loss	$ (15,705,000)	$ (12,762,000)	$ (14,052,000)	$ (15,034,000)	$ (14,990,000)	$ (17,107,000)	$ (10,892,000)	$ (14,257,000)	$ (57,588,000)	$ (57,246,000)	$ (45,722,000)
Denominator for basic loss per share:
Weighted average shares | shares									41,521,629	21,993,066	4,239,564
Basic loss per share attributable to ConforMIS, Inc. stockholders (in dollars per share) | $ / shares									$ (1.39)	$ (2.60)	$ (10.78)
Diluted loss per share attributable to ConforMIS, Inc. stockholders (in dollars per share) | $ / shares									$ (1.39)	$ (2.60)	$ (10.78)

Summary of Significant Accoun47

Summary of Significant Accounting Policies Summary of Significant Accounting Policies (Schedule of Accumulated Other Comprehensive Income (Loss)) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Accumulated Other Comprehensive Income (Loss) [Line Items]
Beginning balance	$ 141,212	$ 49,827	$ 68,960
Change in period	1,020	(24)	(613)
Ending balance	94,055	141,212	49,827
Foreign currency translation adjustments
Accumulated Other Comprehensive Income (Loss) [Line Items]
Beginning balance	(521)
Change in period	1,027
Ending balance	506	(521)
Change in unrealized gain (loss) on available-for-sale securities, net of tax
Accumulated Other Comprehensive Income (Loss) [Line Items]
Beginning balance	0
Change in period	(7)
Ending balance	(7)	0
Accumulated other comprehensive income (loss)
Accumulated Other Comprehensive Income (Loss) [Line Items]
Beginning balance	(521)	(497)	116
Change in period	1,020	(24)	(613)
Ending balance	$ 499	$ (521)	$ (497)

Summary of Significant Accoun48

Summary of Significant Accounting Policies (Schedule of Antidilutive Securities Excluded from Computation of Earnings Per Share) (Details) - shares	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Antidilutive Securities Excluded from Computation of Earnings Per Share
Anti-dilutive shares not included in the calculation of diluted net loss per share	1,993,739	16,932,765	27,394,765
Preferred stock | Series A convertible preferred stock
Antidilutive Securities Excluded from Computation of Earnings Per Share
Anti-dilutive shares not included in the calculation of diluted net loss per share	0	873,591	1,705,138
Preferred stock | Series B convertible preferred stock
Antidilutive Securities Excluded from Computation of Earnings Per Share
Anti-dilutive shares not included in the calculation of diluted net loss per share	0	1,144,885	2,234,668
Preferred stock | Series C convertible preferred stock
Antidilutive Securities Excluded from Computation of Earnings Per Share
Anti-dilutive shares not included in the calculation of diluted net loss per share	0	1,256,752	2,453,018
Preferred stock | Series D convertible preferred stock
Antidilutive Securities Excluded from Computation of Earnings Per Share
Anti-dilutive shares not included in the calculation of diluted net loss per share	0	3,410,570	6,415,106
Preferred stock | Series E-1 convertible preferred stock
Antidilutive Securities Excluded from Computation of Earnings Per Share
Anti-dilutive shares not included in the calculation of diluted net loss per share	0	3,748,578	6,530,429
Preferred stock | Series E-2 convertible preferred stock
Antidilutive Securities Excluded from Computation of Earnings Per Share
Anti-dilutive shares not included in the calculation of diluted net loss per share	0	2,628,037	5,129,592
Warrants | Preferred stock warrants | Series C convertible preferred stock
Antidilutive Securities Excluded from Computation of Earnings Per Share
Anti-dilutive shares not included in the calculation of diluted net loss per share	0	0	56,202
Warrants | Preferred stock warrants | Series D convertible preferred stock
Antidilutive Securities Excluded from Computation of Earnings Per Share
Anti-dilutive shares not included in the calculation of diluted net loss per share	0	0	58,365
Warrants | Preferred stock warrants | Series E-2 convertible preferred stock
Antidilutive Securities Excluded from Computation of Earnings Per Share
Anti-dilutive shares not included in the calculation of diluted net loss per share	0	0	5,883
Warrants | Common stock warrants
Antidilutive Securities Excluded from Computation of Earnings Per Share
Anti-dilutive shares not included in the calculation of diluted net loss per share	34,709	303,931	25,733
Equity options
Antidilutive Securities Excluded from Computation of Earnings Per Share
Anti-dilutive shares not included in the calculation of diluted net loss per share	1,959,030	3,566,421	2,780,631

Summary of Significant Accoun49

Summary of Significant Accounting Policies (Reclassification) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Error Corrections and Prior Period Adjustments Restatement [Line Items]
Cost of revenue	$ 53,192	$ 45,102	$ 32,374
Selling and Marketing Expense	(41,086)	(37,558)	(29,367)
Improper Classification of Cost of Revenue [Member]
Error Corrections and Prior Period Adjustments Restatement [Line Items]
Cost of revenue	$ 3,500
Restatement Adjustment [Member] | Improper Classification of Cost of Revenue [Member]
Error Corrections and Prior Period Adjustments Restatement [Line Items]
Cost of revenue		2,700	1,700
Selling and Marketing Expense		$ 2,700	$ 1,700

Fair Value Measurements (Schedu

Fair Value Measurements (Schedule of Fair Value, Assets and Liabilities Measured on Recurring Basis) (Details) - USD ($) $ in Thousands	Dec. 31, 2016	Dec. 31, 2015
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cash	$ 8,504	$ 10,302
Cash and cash equivalents	8,504	10,302
Available-for-sale Securities, Accumulated Gross Unrealized Gain, before Tax	0	0
Gross Unrealized Losses	(7)	0
Total, Amortized Costs	65,506	117,185
Total, Fair Value	65,499	117,185
Cash and cash equivalents
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cash and cash equivalents	8,504	10,302
Total, Fair Value	37,257	117,185
Short-term investments
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cash and cash equivalents	0	0
Total, Fair Value	28,242	0
Money market funds
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Amortized Cost	28,753	106,883
Available-for-sale Securities, Accumulated Gross Unrealized Gain, before Tax	0	0
Gross Unrealized Losses	0	0
Money market funds | Level 1 securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Estimated Fair Value	28,753	106,883
Money market funds | Cash and cash equivalents | Level 1 securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Estimated Fair Value	28,753	106,883
Money market funds | Short-term investments | Level 1 securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Estimated Fair Value	0	$ 0
Corporate bonds
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Amortized Cost	6,701
Available-for-sale Securities, Accumulated Gross Unrealized Gain, before Tax	0
Gross Unrealized Losses	(4)
Corporate bonds | Level 2 securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Estimated Fair Value	6,697
Corporate bonds | Cash and cash equivalents | Level 2 securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Estimated Fair Value	0
Corporate bonds | Short-term investments | Level 2 securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Estimated Fair Value	6,697
Agency bond
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Amortized Cost	21,548
Available-for-sale Securities, Accumulated Gross Unrealized Gain, before Tax	0
Gross Unrealized Losses	(3)
Agency bond | Level 2 securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Estimated Fair Value	21,545
Agency bond | Cash and cash equivalents | Level 2 securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Estimated Fair Value	0
Agency bond | Short-term investments | Level 2 securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Estimated Fair Value	$ 21,545

Accounts Receivable (Details)

Accounts Receivable (Details) - USD ($)	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Accounts Receivable, Net, Current [Abstract]
Total receivables	$ 15,356,000	$ 15,421,000
Allowance for doubtful accounts and returns	(681,000)	(554,000)
Accounts receivable, net	14,675,000	14,867,000
Unbilled receivable	2,500,000	1,300,000
Accounts receivable write offs	$ 41,000	$ 88,000	$ 70,000

Accounts Receivable (Details 2)

Accounts Receivable (Details 2) - USD ($)	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Allowance For Doubtful Accounts Receivable [Line Items]
Beginning balance	$ (554,000)	$ (162,000)
Provision for bad debts on trade receivables	(188,000)	(359,000)	$ (6,000)
Accounts receivable write offs	41,000	88,000	70,000
Ending balance	(681,000)	(554,000)	$ (162,000)
Trade Accounts Receivable
Allowance For Doubtful Accounts Receivable [Line Items]
Provision for bad debts on trade receivables	(188,000)	(359,000)
Other Receivable
Allowance For Doubtful Accounts Receivable [Line Items]
Other allowances	$ 20,000	$ (121,000)

Inventories (Details)

Inventories (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015
Inventory Disclosure [Abstract]
Raw Material	$ 3,331	$ 4,175
Work in process	2,530	2,683
Finished goods	5,859	4,662
Total Inventories	11,720	11,520
Inventories write-downs	$ 200	300
Inventories reserves		$ 37

Property and Equipment (Details

Property and Equipment (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Property and equipment
Total property and equipment	$ 25,386	$ 18,600
Accumulated depreciation	(10,302)	(7,634)
Property and equipment, net	15,084	10,966
Depreciation expense	2,900	2,400	$ 1,800
Equipment
Property and equipment
Total property and equipment	$ 16,651	12,185
Equipment | Minimum
Property and equipment
Estimated useful life	5 years
Equipment | Maximum
Property and equipment
Estimated useful life	7 years
Furniture and fixtures
Property and equipment
Total property and equipment	$ 414	391
Furniture and fixtures | Minimum
Property and equipment
Estimated useful life	5 years
Furniture and fixtures | Maximum
Property and equipment
Estimated useful life	7 years
Computer and software
Property and equipment
Total property and equipment	$ 7,027	5,229
Estimated useful life	3 years
Leasehold improvements
Property and equipment
Total property and equipment	$ 1,294	$ 795
Leasehold improvements | Minimum
Property and equipment
Estimated useful life	2 years
Leasehold improvements | Maximum
Property and equipment
Estimated useful life	7 years

Intangible Assets (Details)

Intangible Assets (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Intangible assets
Intangible assets, net	$ 746	$ 995
Estimated useful life	10 years
Amortization expense	$ 200	200	$ 200
Weighted Average
Intangible assets
Estimated useful life	3 years
Developed technology
Intangible assets
Total intangible assets	$ 979	979
Accumulated amortization	(681)	(582)
Intangible assets, net	$ 298	397
Estimated useful life	10 years
License agreements
Intangible assets
Total intangible assets	$ 1,508	1,508
Accumulated amortization	(1,060)	(910)
Intangible assets, net	$ 448	$ 598
Estimated useful life	10 years

Intangible Assets (Details 2)

Intangible Assets (Details 2) - USD ($) $ in Thousands	Dec. 31, 2016	Dec. 31, 2015
Estimated future amortization expense for intangible assets
2,017	$ 249
2,018	249
2,019	248
Intangible assets, net	$ 746	$ 995

Accrued Expenses (Details)

Accrued Expenses (Details) - USD ($) $ in Thousands	Dec. 31, 2016	Dec. 31, 2015
Accrued Liabilities and Other Liabilities [Abstract]
Accrued employee compensation	$ 4,037	$ 3,585
Deferred rent	101	213
Accrued legal expense	710	334
Accrued consulting expense	104	134
Accrued vendor charges	1,396	692
Accrued revenue share expense	992	932
Accrued patent settlement and license costs	0	500
Accrued clinical trial expense	256	302
Accrued other	896	1,119
Total	$ 8,492	$ 7,811

Deferred Revenue (Details)

Deferred Revenue (Details) - Royalty Arrangement $ in Millions	Apr. 30, 2015USD ($)
Wright Medical and MicroPort
Deferred Revenue
Aggregate deferred royalty revenue	$ 5.1
Wright Medical
Deferred Revenue
Aggregate deferred royalty revenue	4.9
MicroPort
Deferred Revenue
Aggregate deferred royalty revenue	$ 0.2

Commitments and Contingencies59

Commitments and Contingencies (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Operating Leases, Future Minimum Payments Due, Fiscal Year Maturity [Abstract]
2,017	$ 1,179
2,018	1,500
2,019	1,537
2,020	1,574
2,021	1,611
2022-2025	4,323
Total	11,724
Rent expense	1,500	$ 1,600	$ 1,500
Deferred rent	$ 300	$ 400	$ 500

Commitments and Contingencies60

Commitments and Contingencies (Details 2)

Jul. 25, 2016USD ($)ft²reduction

May 27, 2016defensepatent

Feb. 29, 2016patent

Nov. 02, 2015plaintiff

Sep. 30, 2011

Feb. 28, 2017patentpetition

Mar. 31, 2018USD ($)

Sep. 30, 2017USD ($)

Sep. 30, 2016USD ($)extension

Dec. 31, 2016USD ($)

Dec. 31, 2015USD ($)

Dec. 31, 2014USD ($)

Sep. 19, 2016ft²

License and revenue share agreements

Additional leased area (square feet) | ft²

18,223

45,043

Rent expense | $

$ 200,000

Annual increase per square foot of monthly rent payments | $

$ 0.50

Security deposit | $

$ 500,000

Number of bi-annual reductions | reduction

3

Bi-annual reduction in security deposits | $

$ (100,000)

Number of renewal options | extension

1

Renewal term

5 years

Annual increase in initial base rental rate

2.00%

Number of motions filed on behalf of persons seeking to be named lead plaintiff | plaintiff

2

Number of Company's patents allegedly infringed upon | patent

9

Number of affirmative defenses alleged | defense

2

Number of patents allegedly infringed | patent

10

Revenue share agreements

License and revenue share agreements

Revenue share expense | $

$ 3,500,000

$ 3,200,000

$ 2,300,000

Revenue share expense as a percentage of product revenues

4.40%

5.00%

5.00%

Members of scientific advisory board | Revenue share agreements | Minimum

License and revenue share agreements

Required payment to related party from net revenues of current and planned products (as a percent)

0.1

Members of scientific advisory board | Revenue share agreements | Maximum

License and revenue share agreements

Required payment to related party from net revenues of current and planned products (as a percent)

1.33

Dr. Philipp Lang | Revenue share agreements

License and revenue share agreements

Revenue share expense | $

$ 1,000,000

$ 800,000

$ 600,000

Dr. Philipp Lang | Revenue share agreements | Minimum

License and revenue share agreements

Required payment to related party from net revenues of current and planned products (as a percent)

0.875

Dr. Philipp Lang | Revenue share agreements | Maximum

License and revenue share agreements

Required payment to related party from net revenues of current and planned products (as a percent)

1.33

Scenario, Forecast

License and revenue share agreements

Rent expense | $

$ 100,000

$ 0

iUni and iDuo

License and revenue share agreements

Number of patents allegedly infringed | patent

2

iTotal

License and revenue share agreements

Number of patents allegedly infringed | patent

3

iUni, iDuo, and iTotal

License and revenue share agreements

Number of patents allegedly infringed | patent

5

Subsequent Event

License and revenue share agreements

Number of Company's patents allegedly infringed upon | patent

9

Number of petitions filed requesting Inter Partes Review | petition

14

Number of patents included in petition requesting Inter Partes Review | patent

8

Commitments and Contingencies61

Commitments and Contingencies (Details 3) $ in Thousands	Dec. 31, 2016USD ($)
Contractual Obligation, Fiscal Year Maturity [Abstract]
Operating leases due in next twelve months	$ 1,179
Operating leases due in two and three years	3,037
Operating leases due in four and five years	3,185
Operating leases due thereafter	4,323
Total	11,724
Other commitment due in next twelve months	484
Other commitment due in second and third year	409
Other commitment due in fourth and fifth year	400
Other commitment due thereafter	125
Other commitment	1,418
Contractual obligation, due in next twelve months	1,663
Contractual obligation due in second and third year	3,446
Contractual obligation due in fourth and fifth year	3,585
Contractual obligation, due thereafter	4,448
Contractual obligation	$ 13,142

Debt and Notes Payable (Details

Debt and Notes Payable (Details)	Jan. 01, 2013Installment	Dec. 31, 2016USD ($)	Jun. 30, 2011USD ($)shares	Dec. 31, 2016USD ($)	Dec. 31, 2015USD ($)	Dec. 31, 2014USD ($)	Sep. 30, 2015USD ($)
Credit facility
Prepayment of remaining loan balance		$ 200,000
Discount recorded to additional paid-in capital for fair value of warrants				$ 0	$ 0	$ 177,000
Massachusetts Development Finance Agency | Term loan
Credit facility
Maximum amount committed by the lenders under the loan and security agreement			$ 1,400,000
Outstanding advances					$ 500,000
Amount drawn down							$ 1,400,000
Period for borrowing remaining funds			18 months
Fixed interest rate (as a percent)		6.50%		6.50%
Number of equal installments to be paid | Installment	66
Credit facility term			84 months
Massachusetts Development Finance Agency | Term loan | Preferred stock warrants | Series D convertible preferred stock
Credit facility
Number of shares of common stock under warrants issued to counterparty | shares			16,000
Discount recorded to additional paid-in capital for fair value of warrants			$ 46,000
Massachusetts Development Finance Agency | Term loan | First tranche
Credit facility
Amount drawn down			$ 600,000

Related Party Transactions (Det

Related Party Transactions (Details)	1 Months Ended		12 Months Ended			93 Months Ended	105 Months Ended	117 Months Ended
	Sep. 30, 2011	Apr. 30, 2007USD ($)$ / sharesshares	Dec. 31, 2016USD ($)$ / sharesshares	Dec. 31, 2015USD ($)$ / sharesshares	Dec. 31, 2014USD ($)$ / sharesshares	Dec. 31, 2014USD ($)$ / sharesshares	Dec. 31, 2015USD ($)$ / sharesshares	Dec. 31, 2016USD ($)$ / sharesshares
Common stock warrants
Related Party Transaction
Number of shares of common stock under warrants issued to counterparty | shares			171,783	751,779	204,312	204,312	751,779	171,783
Exercise price of warrants issued to counterparty (in dollars per share) | $ / shares			$ 7.47	$ 10.30	$ 8.90	$ 8.90	$ 10.30	$ 7.47
Revenue share agreements
Related Party Transaction
Revenue share expense			$ 3,500,000	$ 3,200,000	$ 2,300,000
Affiliate | Vertegen | License agreement
Related Party Transaction
Initial license fee paid		$ 10,000
Initial royalty rate on net sales of products under the agreement (as a percent)			6.00%					6.00%
Reduced royalty rate on net sales of products following expiration of patents (as a percent)			3.00%					3.00%
Royalty payments								$ 0
Expenses in connection with preparation of patent applications						$ 140,000,000	$ 140,000	$ 150,000
Affiliate | Vertegen | License agreement | United States
Related Party Transaction
Period for reduced royalty rate			5 years
Affiliate | Vertegen | License agreement | Rest of World
Related Party Transaction
Period for reduced royalty rate			5 years
Affiliate | Vertegen | License agreement | Common stock warrants
Related Party Transaction
Number of shares of common stock under warrants issued to counterparty | shares		100,000
Exercise price of warrants issued to counterparty (in dollars per share) | $ / shares		$ 1.10
Dr. Philipp Lang | Revenue share agreements
Related Party Transaction
Revenue share expense			$ 1,000,000	$ 800,000	$ 600,000
Dr. Philipp Lang | Revenue share agreements | Minimum
Related Party Transaction
Required payment to related party from net revenues of current and planned products (as a percent)	0.875
Dr. Philipp Lang | Revenue share agreements | Maximum
Related Party Transaction
Required payment to related party from net revenues of current and planned products (as a percent)	1.33

Stockholders' Equity (Details T

Stockholders' Equity (Details Textual)	Jun. 16, 2015	Dec. 31, 2016USD ($)vote$ / sharesshares	Dec. 31, 2015$ / sharesshares	Dec. 31, 2014shares	Jul. 07, 2015$ / sharesshares
Common stock
Issuance of common stock - IPO			10,350,000
Common stock, shares authorized		200,000,000	200,000,000
Common stock dividends declared to date | $		$ 0
Number of votes per share of common stock | vote		1
Common stock, shares outstanding, beginning balance (in shares)		41,110,127	4,286,164
Issuance of common stock - option & warrant exercises		1,485,401	395,192
Issuance of restricted common stock		804,019	174,530
Issuance of common stock - preferred stock conversion to common stock		25,904,241	25,904,241
Common stock, shares outstanding, ending balance (in shares)		43,399,547	41,110,127	4,286,164
Preferred stock
Preferred stock, shares authorized		5,000,000	5,000,000		5,000,000
Preferred stock, par value (in dollars per share) | $ / shares		$ 0.00001	$ 0.00001
Preferred stock, shares issued		0	0
Preferred stock, shares outstanding		0	0
Common Stock
Common stock
Reverse stock split ratio	1
Issuance of common stock - IPO			10,350,000
Common stock, shares outstanding, beginning balance (in shares)		41,110,127	4,286,164	4,161,178
Issuance of common stock - preferred stock conversion to common stock			25,904,241
Common stock, shares outstanding, ending balance (in shares)		43,399,547	41,110,127	4,286,164
Preferred stock
Preferred stock, par value (in dollars per share) | $ / shares					$ 0.00001

Stockholders' Equity (Schedule

Stockholders' Equity (Schedule of Stock by Class) (Details) $ in Millions	Dec. 31, 2016USD ($)occasion
Registration Rights Agreement, Other Than Form S-3
Demand registration rights
Minimum ownership of outstanding shares for holders to exercise demand registration rights (as a percent)	25.00%
Minimum offering relative to outstanding shares to trigger demand registration rights (as a percent)	20.00%
Minimum aggregate offering price to trigger demand registration rights | $	$ 20
Maximum number of registration statements under demand registration rights | occasion	2
Registration Rights Agreement, Form S-3
Demand registration rights
Minimum ownership of outstanding shares for holders to exercise demand registration rights (as a percent)	25.00%
Minimum offering relative to outstanding shares to trigger demand registration rights (as a percent)	25.00%
Minimum aggregate offering price to trigger demand registration rights | $	$ 5
Maximum number of registration statements under demand registration rights | occasion	1

Stockholders' Equity (Class of

Stockholders' Equity (Class of Warrant or Right) (Details) - $ / shares	3 Months Ended	12 Months Ended
	Mar. 31, 2015	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Stock warrant activity
Number of warrants, cancelled/expired (in shares)		(413,331)
Weighted average exercise price, cancelled/expired (in dollars per share)		$ 0
Weighted average price, cancelled/expired (in dollars per share)		$ 0
Preferred stock warrants | Series C convertible preferred stock
Stock warrant activity
Number of warrants, outstanding at beginning of period (in shares)		0
Number of warrants, outstanding at end of period (in shares)		0	0
Common stock warrants
Warrants
Number of shares of common stock warrants issued to purchase (in shares)		1,138,424
Stock warrant activity
Number of warrants, outstanding at beginning of period (in shares)	204,312	751,779	204,312
Number of warrants, exercised (in shares)		(166,665)	(16,721)
Number of warrants, converted to common warrant (in shares)	(564,188)		(564,188)
Number of warrants, outstanding at end of period (in shares)		171,783	751,779	204,312
Weighted average exercise price, outstanding at beginning of period	$ 8.90	$ 10.30	$ 8.90
Weighted average exercise price, exercised (in dollars per share)		9	7.80
Weighted average exercise price, converted from common warrant (in dollars per share)			10.73
Weighted average exercise price, outstanding at end of period		$ 7.47	$ 10.30	$ 8.90
Number of exercisable warrants, outstanding at beginning of period (in shares)	204,312	751,779	204,312
Number of exercisable warrants, exercised (in shares)		(166,665)	(16,721)
Number of exercisable warrants, canceled/expired (in shares)		(413,331)
Number of exercisable warrants, converted from common warrant (in shares)			564,188
Number of exercisable warrants, outstanding at end of period (in shares)		171,783	751,779	204,312
Weighted average price, outstanding at beginning of period (in dollars per share)	$ 8.90	$ 10.30	$ 8.90
Weighted average price, exercised (in dollars per share)		9	$ 7.80
Weighted average price, converted from common common warrant (in dollars per share)			10.73
Weighted average price, outstanding at end of period (in dollars per share)		$ 7.47	$ 10.30	$ 8.90
Weighted average contractual life		1 year 7 months 13 days	1 year 3 months 29 days	3 years 3 months 4 days
Minimum | Common stock warrants
Warrants
Exercise price of warrants or rights issued to date		$ 0.02
Maximum | Common stock warrants
Warrants
Exercise price of warrants or rights issued to date		$ 9
Warrants
Assumptions used in estimating fair value of warrants at date of grant
Dividend yield (as a percent)				0.00%
Warrants | Minimum
Assumptions used in estimating fair value of warrants at date of grant
Risk-free interest rate (as a percent)				0.91%
Expected term				2 years 6 months
Expected volatility (as a percent)				50.00%
Warrants | Maximum
Assumptions used in estimating fair value of warrants at date of grant
Risk-free interest rate (as a percent)				1.71%
Expected term				5 years
Expected volatility (as a percent)				55.00%

Stockholders' Equity (Schedul67

Stockholders' Equity (Schedule of Share-based Compensation Arrangements by Share-based Payment Award) (Details) $ / shares in Units, $ in Thousands	1 Months Ended			12 Months Ended
	Jun. 30, 2015	May 31, 2015program	Feb. 28, 2011	Dec. 31, 2016USD ($)$ / sharesshares	Dec. 31, 2015$ / sharesshares	Dec. 31, 2014$ / sharesshares
Aggregate Intrinsic Value
Exercised | $				$ 8,219
Balance outstanding at the end of the period | $				8,547
Total vested and exercisable | $				8,514
Share-based Compensation Arrangement by Share-based Payment Award, Options, Vested and Expected to Vest [Abstract]
Weighted average grant date fair value, vested | $				$ 1,900
Weighted average remaining contractual term, vested and exercisable				5 years 6 months 18 days
Weighted average remaining contractual term, outstanding				5 years 22 days
Stock options
Number of Options
Balance outstanding at the beginning of the period (in shares)				5,248,329	5,355,567	4,869,330
Granted (in shares)				179,178	403,086	1,037,547
Exercised (in shares)				(1,467,692)	(383,458)	(118,738)
Expired (in shares)				(81,251)	(30,876)	(142,206)
Cancelled/Forfeited (in shares)				(88,524)	(95,990)	(290,366)
Balance outstanding at the end of the period (in shares)				3,790,040	5,248,329	5,355,567
Total vested and exercisable (in shares)				3,231,167
Weighted Average Exercise Price per Share
Balance at the beginning of the period (in dollars per share) | $ / shares				$ 5.56	$ 4.87	$ 3.77
Granted (in dollars per shares) | $ / shares				8.78	12.20	9.77
Exercised (in dollars per share) | $ / shares				2.78	2.10	1.50
Expired (in dollars per share) | $ / shares				9.70	5.97	5.29
Cancelled/Forfeited (in dollars per share) | $ / shares				9.93	7.42	5.08
Balance at the end of the period (in dollars per share) | $ / shares				6.60	$ 5.56	$ 4.87
Total vested and exercisable | $ / shares				$ 6.01
Restricted stock awards
Share-based Compensation Arrangement by Share-based Payment Award, Options, Vested and Expected to Vest [Abstract]
Weighted average grant date fair value, vested | $				$ 700
2004 Plan | Stock options
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting period			4 years
Expiration period			10 years
2011 Plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of equity programs | program		2
2011 Plan | Stock options
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting period	4 years
Expiration period	10 years
2015 Plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Common stock reserved for issuance, before transfers and annual increases (in shares)				2,000,000
Maximum annual increase in common stock available for issuance (in shares)				3,000,000
Maximum annual increase in common stock available for issuance (as a percent)				3.00%
Common stock available for future issuance (in shares)				1,318,370
2015 Plan | Stock options
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting period				4 years
Expiration period				10 years

Stockholders' Equity (Schedul68

Stockholders' Equity (Schedule of Restricted Common Stock Award Activity) (Details) - USD ($) $ / shares in Units, $ in Millions	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015
Weighted Average Fair Value
Weighted average grant date fair value, vested	$ 1.9
Restricted stock awards
Number of Shares
Unvested beginning of period (in shares)	174,530	0
Granted (in shares)	873,589	174,530
Vested (in shares)	(66,839)
Forfeited (in shares)	(69,570)
Unvested end of period (in shares)	911,710	174,530
Weighted Average Fair Value
Unvested beginning of period (in dollars per share)	$ 22.31	$ 0
Granted (in dollars per share)	8.61	22.31
Vested (in dollars per share)	17.72
Forfeited (in dollars per share)	11.83
Unvested end of period (in dollars per share)	$ 10.32	$ 22.31
Weighted average grant date fair value, vested	$ 0.7

Stockholders' Equity (Fair Valu

Stockholders' Equity (Fair Value of Options at Date of Grant) (Details) - Stock options - $ / shares	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Weighted average fair value of options granted	$ 4.46	$ 5.52	$ 4.40
Assumptions used to estimate the fair value of options at date of grant
Risk-free interest rate, minimum (as a percent)	1.98%	1.37%	1.66%
Risk-free interest rate, maximum (as a percent)	1.98%	1.77%	2.29%
Expected term	6 years 3 months
Dividend yield	0.00%	0.00%	0.00%
Expected volatility (as a percent)	51.00%		50.00%
Minimum
Assumptions used to estimate the fair value of options at date of grant
Expected term		5 years 5 months 19 days	5 years
Expected volatility (as a percent)		49.00%
Maximum
Assumptions used to estimate the fair value of options at date of grant
Expected term		6 years 5 months 12 days	7 years 3 months
Expected volatility (as a percent)		50.00%

Stockholders' Equity (Schedul70

Stockholders' Equity (Schedule of Employee Service Share-based Compensation, Allocation of Recognized Period Costs) (Details) - USD ($)	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Share-based compensation
Stock-based compensation expense	$ 5,324,000	$ 3,607,000	$ 2,550,000
Unrecognized compensation expense	$ 2,200,000	2.4
Period for unrecognized compensation expense to be recognized	2 years 4 months 6 days
Cost of revenues
Share-based compensation
Stock-based compensation expense	$ 333,000	239,000	162,000
Sales and marketing
Share-based compensation
Stock-based compensation expense	1,197,000	730,000	597,000
Research and development
Share-based compensation
Stock-based compensation expense	1,466,000	784,000	628,000
General and administrative
Share-based compensation
Stock-based compensation expense	2,328,000	$ 1,854,000	$ 1,163,000
Restricted stock awards
Share-based compensation
Unrecognized compensation expense	$ 0

Income Taxes Income Taxes (Deta

Income Taxes Income Taxes (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Income Tax Disclosure [Abstract]
U.S.	$ (51,576)	$ (50,155)	$ (40,328)
Non‑U.S.	(5,949)	(7,050)	(5,353)
Income (Loss) from Continuing Operations before Income Taxes, Extraordinary Items, Noncontrolling Interest	$ (57,525)	$ (57,205)	$ (45,681)

Income Taxes (Schedule of Incom

Income Taxes (Schedule of Income Before Income Tax, Domestic and Foreign) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Income (loss) from continuing operations before income taxes:
U.S.	$ (51,576)	$ (50,155)	$ (40,328)
Non‑U.S.	(5,949)	(7,050)	(5,353)
Loss before income taxes	$ (57,525)	$ (57,205)	$ (45,681)

Income Taxes (Schedule of Effec

Income Taxes (Schedule of Effective Income Tax Rate Reconciliation) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Current:
Federal	$ 0	$ 0	$ 0
State	0	0	0
Foreign	63	41	41
Total	63	41	41
Deferred:
Federal	0	0	0
State	0	0	0
Foreign	0	0	0
Total	$ 63	$ 41	$ 41
Tax at U.S. statutory rate	(34.00%)	(34.00%)	(34.00%)
State taxes, net of federal benefits	(2.70%)	(2.27%)	(2.36%)
Permanent items	0.42%	1.52%	1.46%
Tax credit	(1.06%)	(0.85%)	(8.59%)
Change in valuation allowance	33.95%	31.07%	37.49%
Foreign rate differential	1.04%	1.68%	0.68%
Rate change	(0.06%)	0.01%	(0.02%)
Uncertain tax positions	2.06%	2.21%	2.97%
Other	0.46%	0.70%	2.47%
Effective income tax rate	0.11%	0.07%	0.10%

Income Taxes (Schedule of Defer

Income Taxes (Schedule of Deferred Tax Assets and Liabilities) (Details) - USD ($) $ in Thousands	Dec. 31, 2016	Dec. 31, 2015
Deferred tax assets:
Federal and state net operating loss carryforwards	$ 115,719	$ 99,823
Foreign net operating loss carryforwards	2,561	2,973
Accrued expenses	280	0
Credits	5,091	4,483
Deferred revenue	1,709	0
Other	5,703	4,138
Total deferred tax assets	131,063	111,417
Valuation allowance	(130,005)	(110,518)
Net deferred tax assets	1,058	899
Deferred tax liabilities:
Fixed assets	(841)	(612)
Intangibles	(217)	(287)
Other	0	0
Net deferred tax liabilities	(1,058)	(899)
Net deferred tax assets	0	0
Current net deferred tax asset	33	15
Long‑term net deferred tax liability	$ (33)	$ (15)

Income Taxes (Narrative) (Detai

Income Taxes (Narrative) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Operating Loss Carryforwards [Line Items]
Valuation allowance	$ 130,005	$ 110,518
Decrease in valuation allowance	(19,500)
Unrecognized tax benefits	4,917	3,730	$ 2,466	$ 1,109
Unrecognized tax benefits, amount netted against deferred tax assets	4,800	3,600
Domestic Tax Authority
Operating Loss Carryforwards [Line Items]
Operating loss carryforwards	324,000
State and Local Jurisdiction
Operating Loss Carryforwards [Line Items]
Operating loss carryforwards		$ 168,000
Germany | Foreign Tax Authority
Operating Loss Carryforwards [Line Items]
Operating loss carryforwards	$ 25,000

Income Taxes (Schedule of Unrec

Income Taxes (Schedule of Unrecognized Tax Benefits) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Income Tax Disclosure [Abstract]
Unrecognized tax benefits beginning of year	$ 1,187	$ 1,264	$ 1,357
Gross change for current year positions	3,730	2,466	1,109
Decrease for prior period positions	4,917	3,730	2,466
Decrease due to settlements and payments	0	0	0
Decrease due to statute limitations	0	0	0
Unrecognized tax benefits end of the year	$ 0	$ 0	$ 0

Segment and Geographic Data (De

Segment and Geographic Data (Details) $ in Thousands	12 Months Ended
	Dec. 31, 2016USD ($)segment	Dec. 31, 2015USD ($)	Dec. 31, 2014USD ($)
Segment Reporting [Abstract]
Number of reportable segments | segment	1
Geographic information for Product Revenue and Property and equipment, net
Product revenue	$ 78,921	$ 62,791	$ 48,186
Property and equipment, net	15,084	10,966
United States
Geographic information for Product Revenue and Property and equipment, net
Product revenue	62,366	47,223	34,350
Property and equipment, net	14,971	10,836
Rest of World
Geographic information for Product Revenue and Property and equipment, net
Product revenue	1,854	1,773	1,287
Property and equipment, net	113	130
Germany
Geographic information for Product Revenue and Property and equipment, net
Product revenue	$ 14,701	$ 13,795	$ 12,549

Employee Savings Plan (Details)

Employee Savings Plan (Details) - USD ($)	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Compensation and Retirement Disclosure [Abstract]
Maximum annual contributions per employee, percent	80.00%
Employer matching contribution, percent of match	50.00%
Employer matching contribution, percent of employees' gross pay	4.00%
Employer discretionary contribution amount	$ 478,000	$ 400,000	$ 377,000

Selected Quarterly Financial 79

Selected Quarterly Financial Information (Unaudited) (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2016	Sep. 30, 2016	Jun. 30, 2016	Mar. 31, 2016	Dec. 31, 2015	Sep. 30, 2015	Jun. 30, 2015	Mar. 31, 2015	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Revenue
Total revenue	$ 21,673	$ 18,643	$ 19,333	$ 20,250	$ 19,071	$ 13,894	$ 19,222	$ 14,700	$ 79,899	$ 66,887	$ 48,186
Gross profit	8,045	5,998	6,001	6,663	6,340	2,762	7,827	4,856	26,707	21,785	15,812
Net loss	$ (15,705)	$ (12,762)	$ (14,052)	$ (15,034)	$ (14,990)	$ (17,107)	$ (10,892)	$ (14,257)	$ (57,588)	$ (57,246)	$ (45,722)
Per Share Data:
Net loss per share - basic and diluted	$ (0.37)	$ (0.31)	$ (0.34)	$ (0.37)	$ (0.37)	$ (0.45)	$ (2.51)	$ (3.32)	$ (1.39)	$ (2.60)	$ (10.78)

Subsequent Events Subsequent Ev

Subsequent Events Subsequent Events (Details) - Subsequent Event - USD ($)	Jan. 09, 2017	Jan. 06, 2017	Jan. 31, 2017
Subsequent Event [Line Items]
Amount of equity able to raise	$ 200,000,000		$ 200,000,000
Term loan | 2017 Secured Loan Agreement
Subsequent Event [Line Items]
Maximum borrowing capacity		$ 50,000,000
Final payment, percent of amount of loans advanced		5.00%
Basis spread on variable rate		0.53%
Term loan facility, term		5 years
Events of default, additional interest rate		5.00%
Events of default, threshold amount		$ 500,000
Oxford Term Loan | Term loan | 2017 Secured Loan Agreement
Subsequent Event [Line Items]
Maximum borrowing capacity			15,000,000
Amount drawn down		15,000,000	15,000,000
Oxford Term Loan B | Term loan | 2017 Secured Loan Agreement
Subsequent Event [Line Items]
Maximum borrowing capacity		15,000,000	15,000,000
Oxford Term Loan C | Term loan | 2017 Secured Loan Agreement
Subsequent Event [Line Items]
Maximum borrowing capacity		$ 20,000,000	$ 20,000,000
LIBOR | Term loan | 2017 Secured Loan Agreement
Subsequent Event [Line Items]
Basis spread on variable rate		6.47%