CONSOLIDATED STATEMENTS OF CONVERTIBLE PREFERRED STOCK AND STOCKHOLDERS' EQUITY (DEFICIT) - USD ($) $ in Thousands	Common Stock	Additional Paid-In Capital	Accumulated Other Comprehensive Income (Loss)	Accumulated Deficit	Total
Balance at Dec. 31, 2012					$ 21,260
Balance (in shares) at Dec. 31, 2012					20,890,000
Increase (Decrease) in Temporary Equity
Accretion of convertible preferred stock to redemption value					$ 1,740
Balance at Dec. 31, 2013					$ 23,000
Balance (in shares) at Dec. 31, 2013					20,890,000
Balance at Dec. 31, 2012				$ (2,190)	$ (2,190)
Balance (in shares) at Dec. 31, 2012	2,730,427
Increase (Decrease) in Stockholders' Equity
Unrealized gain (loss) on marketable securities			$ 3		3
Accretion of convertible preferred stock, equity effect				(1,740)	(1,740)
Net loss				(5,236)	(5,236)
Balance at Dec. 31, 2013			3	(9,166)	(9,163)
Balance (in shares) at Dec. 31, 2013	2,730,427
Increase (Decrease) in Temporary Equity
Issuance of convertible preferred stock, net of issuance costs					$ 11,623
Issuance of convertible preferred stock (in shares)					6,451,057
Accretion of convertible preferred stock to redemption value					$ 2,054
Balance at Dec. 31, 2014					$ 36,677
Balance (in shares) at Dec. 31, 2014					27,341,057
Increase (Decrease) in Stockholders' Equity
Unrealized gain (loss) on marketable securities			(9)		$ (9)
Equity Impact of Purchase Put Option				(1,039)	(1,039)
Stock-based compensation expense		$ 27			27
Accretion of convertible preferred stock, APIC effect		(27)
Accretion of convertible preferred stock, equity effect				(2,027)	(2,054)
Net loss				(8,517)	(8,517)
Balance at Dec. 31, 2014			(6)	(20,749)	$ (20,755)
Balance (in shares) at Dec. 31, 2014	2,730,427				2,730,427
Increase (Decrease) in Temporary Equity
Issuance of convertible preferred stock, net of issuance costs					$ 39,864
Issuance of convertible preferred stock (in shares)					12,944,984
Issuance of common stock upon conversion of convertible preferred stock					$ (78,305)
Conversion of convertible preferred stock into permanent equity (in shares)					(40,286,041)
Accretion of convertible preferred stock to redemption value					$ 1,764
Increase (Decrease) in Stockholders' Equity
Stock Issued During Period, Value, New Issues		56,550			56,550
Stock Issued During Period, Shares, New Issues	5,750,000
Stock Issued During Period, Value, Conversion of Convertible Securities		78,305			78,305
Stock Issued During Period, Shares, Conversion of Convertible Securities	11,677,076
Unrealized gain (loss) on marketable securities			(148)		(148)
Foreign currency translation adjustment			5		5
Stock-based compensation expense		891			891
Accretion of convertible preferred stock, APIC effect		(243)
Accretion of convertible preferred stock, equity effect				(1,521)	(1,764)
Net loss				(20,563)	(20,563)
Balance at Dec. 31, 2015		$ 135,503	$ (149)	$ (42,833)	$ 92,521
Balance (in shares) at Dec. 31, 2015	20,157,503				20,157,503