Consolidated Statements of Convertible Preferred Stock and Stockholders' Equity (Deficit) - USD ($) $ in Thousands	Total	IPO	Private Placement	Market Offering	Convertible Preferred Stock	Convertible Preferred Stock Series C Convertible Preferred Stock	Convertible Preferred Stock Series B Convertible Preferred Stock	Convertible Preferred Stock Series D Convertible Preferred Stock	Convertible Preferred Stock Series E Convertible Preferred Stock	Common Stock	Common Stock IPO	Common Stock Private Placement	Common Stock Market Offering	Additional Paid In Capital	Additional Paid In Capital IPO	Additional Paid In Capital Private Placement	Additional Paid In Capital Market Offering	Accumulated Other Comprehensive Income	Retained Earnings
Beginning balance at Dec. 31, 2013					$ 32,224
Beginning balance at Dec. 31, 2013	$ (38,758)													$ 5,871					$ (44,629)
Beginning balance, Shares at Dec. 31, 2013					22,041,003
Beginning balance, Shares at Dec. 31, 2013										295,498
Issuance of convertible preferred stock for cash, net of issuance costs						$ 41,888		$ 48,918
Issuance of convertible preferred stock for cash, net of issuance costs (in shares)						19,423,965		19,012,173
Issuance of convertible preferred stock upon conversion of convertible promissory notes						$ 13,452	$ 4,956
Issuance of convertible preferred stock upon conversion of convertible promissory notes, Shares						6,199,217	2,931,981
Effects of Series C convertible preferred stock tranche						$ (1,475)
Reclassification of common stock warrants	784													784
Convertible promissory notes beneficial conversion feature	57													57
Reacquisition of equity component of Series B convertible promissory note	(3,432)													(3,432)
Reacquisition of convertible promissory notes beneficial conversion feature	(3,553)													(3,553)
Issuance of common stock upon exercise of stock options	$ 49													49
Issuance of common stock upon exercise of stock options, Shares	66,499									66,499
Stock-based compensation	$ 570													570
Net loss	(17,014)																		(17,014)
Ending balance at Dec. 31, 2014					$ 139,963
Ending balance at Dec. 31, 2014	(61,297)													346					(61,643)
Ending balance, Shares at Dec. 31, 2014					69,608,339
Ending balance, Shares at Dec. 31, 2014										361,997
Issuance of convertible preferred stock for cash, net of issuance costs									$ 24,992
Issuance of convertible preferred stock for cash, net of issuance costs (in shares)									2,361,029
Issuance of convertible preferred stock upon exercise of preferred stock warrants					$ 9
Issuance of convertible preferred stock upon exercise of preferred stock warrants, Shares					6,668
Conversion of convertible preferred stock to common stock	164,964				$ (164,964)					$ 5				164,959
Conversion of convertible preferred stock to common stock (in shares)					(71,976,036)					51,822,659
Issuance of common stock		$ 124,193	$ 25,000								$ 1				$ 124,192	$ 25,000
Issuance of common stock (in shares)											8,050,000	1,470,588
Reclassification of convertible preferred stock and common stock warrant liability to additional paid-in capital	$ 27,066													27,066
Issuance of common stock upon exercise of stock options, Shares	836,241
Issuance of common stock upon exercise of stock options and grant of restricted stock	$ 673													673
Issuance of common stock upon exercise of stock options and grant of restricted stock, Shares										843,441
Issuance of common stock upon exercise of warrants	117													117
Issuance of common stock upon exercise of warrants, Shares										302,269
Issuance of common stock in business acquisition	11,452													11,452
Issuance of common stock in business acquisition, Shares										697,306
Issuance of common stock under Employee Stock Purchase Plan	572													572
Issuance of common stock under Employee Stock Purchase Plan, Shares										39,573
Stock-based compensation	8,430													8,430
Other comprehensive loss	(339)																	$ (339)
Net loss	(39,209)																		(39,209)
Ending balance at Dec. 31, 2015					$ 0
Ending balance at Dec. 31, 2015	$ 261,622									$ 6				362,807				(339)	(100,852)
Ending balance, Shares at Dec. 31, 2015	63,587,833									63,587,833
Issuance of common stock				$ 36,806									$ 1				$ 36,805
Issuance of common stock (in shares)													2,526,229
Issuance of common stock upon exercise of stock options	$ 903													903
Issuance of common stock upon exercise of stock options, Shares	873,735									873,735
Issuance of common stock upon exercise of warrants	$ 97													97
Issuance of common stock upon exercise of warrants, Shares										831,513
Issuance of common stock under Employee Stock Purchase Plan	835													835
Issuance of common stock under Employee Stock Purchase Plan, Shares										98,936
Stock-based compensation	15,006													15,006
Excess tax benefit from stock-based compensation	4,444													4,444
Other comprehensive loss	(1,345)																	(1,345)
Net loss	(91,148)																		(91,148)
Ending balance at Dec. 31, 2016	$ 227,220									$ 7				$ 420,897				$ (1,684)	$ (192,000)
Ending balance, Shares at Dec. 31, 2016	67,918,246									67,918,246