CONSOLIDATED STATEMENTS OF STOCKHOLDERS’ EQUITY (DEFICIT) (USD $) In Thousands, except Share data, unless otherwise specified	Total	Series A-1 Preferred Stock [Member]	Series A-2 Preferred Stock [Member]	Series B Preferred Stock [Member]	Common Stock [Member]	Treasury Stock [Member]	Additional Paid-in Capital [Member]	Accumulated Other Comprehensive Income (Loss) [Member]	Accumulated Deficit [Member]
Beginning Balance at Dec. 31, 2011	$ (22,170)	$ 11	$ 18	$ 15	$ 5		$ 25,105	$ (1,199)	$ (46,125)
Beginning Balance (in shares) at Dec. 31, 2011		11,120,119	18,097,848	14,838,368	4,577,240
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Issuance of common stock (in shares)					1,305
Issuance of common stock	71						71
Options exercised (in shares)					(63,598)
Exercises of common stock options	132						132
Stock-based compensation	295						295
Currency translation adjustment	742							742
Net loss	(9,701)								(9,701)
Ending Balance at Dec. 31, 2012	(30,631)	11	18	15	5		25,603	(457)	(55,826)
Ending Balance (in shares) at Dec. 31, 2012		11,120,119	18,097,848	14,838,368	4,642,143
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Issuance of common stock (in shares)					5,750,000
Issuance of common stock	86,250				6		86,244
Underwriting discount and common stock issuance costs	(8,744)						(8,744)
Conversion of preferred stock to common stock in connection with the initial public offering (in shares)					10,977,667
Conversion of preferred stock to common stock in connection with the initial public offering	35,000				11		35,033
Dividends on Series C Preferred Stock (in shares)		(11,120,119)	(18,097,848)	(14,838,368)
Dividends on Series C Preferred Stock	(17,143)	(11)	(18)	(15)			(17,143)
Conversion of convertible notes (in shares)					1,929,309
Conversion of convertible notes	28,957				2		28,955
Reclassification of warrant liability to equity	9,760						9,760
Exercise of preferred stock warrant (in shares)					10,889
Exercise of preferred stock warrant	0
Exercise of common stock warrant (in shares)					650,669
Exercise of common stock warrant	4						4
Options exercised (in shares)					(115,990)
Exercises of common stock options	235						235
Stock-based compensation	1,269						1,269
Currency translation adjustment	655							655
Net loss	(27,935)								(27,935)
Ending Balance at Dec. 31, 2013	77,677	0	0	0	24		161,216	198	(83,761)
Ending Balance (in shares) at Dec. 31, 2013		0	0	0	24,076,667
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Issuance of common stock (in shares)					1,495,000
Issuance of common stock	36,628				2		36,626
Underwriting discount and common stock issuance costs	(2,634)						(2,634)
Options exercised (in shares)	(652,605)				(652,605)
Exercises of common stock options	2,363				1		2,362
Issuance of common stock under employee stock purchase plan (in shares)					233,244
Issuance of common stock under employee stock purchase plan	3,125						3,125
Purchase of treasury stock (in shares)						349
Purchase of treasury stock	(8)					(8)
Stock-based compensation	5,225						5,225
Currency translation adjustment	(3,698)							(3,698)
Net loss	(10,977)								(10,977)
Treasury Stock Ending Balance (in shares)						349
Ending Balance at Dec. 31, 2014	$ 107,701	$ 0	$ 0	$ 0	$ 27	$ (8)	$ 205,920	$ (3,500)	$ (94,738)
Ending Balance (in shares) at Dec. 31, 2014		0	0	0	26,457,516