CONDENSED CONSOLIDATED STATEMENTS OF STOCKHOLDERS' EQUITY (Unaudited) - USD ($) $ in Thousands	Total	Common Stock	Additional Paid-in Capital	Accumulated Other Comprehensive Income (Loss)	Accumulated Deficit
Beginning balance at Dec. 31, 2019	$ 53,739	$ 21	$ 319,115	$ 44	$ (265,441)
Beginning balance, shares at Dec. 31, 2019		20,851,531
Issuance of common stock upon exercise of options	40		40
Issuance of common stock upon exercise of options, shares		24,687
Issuance of common stock with restricted stock units and awards	58		58
Issuance of common stock with restricted stock units and awards, shares		40,931
Stock-based compensation expense	1,447		1,447
Foreign currency translation adjustments	(71)			(71)
Net loss	(13,844)				(13,844)
Ending balance at Mar. 31, 2020	41,369	$ 21	320,660	(27)	(279,285)
Ending balance, shares at Mar. 31, 2020		20,917,149
Beginning balance at Dec. 31, 2020	113,905	$ 26	430,781	41	(316,943)
Beginning balance, shares at Dec. 31, 2020		25,722,984
Issuance of common stock upon exercise of options	761		761
Issuance of common stock upon exercise of options, shares		77,892
Issuance of common stock with restricted stock units and awards	47		47
Issuance of common stock with restricted stock units and awards, shares		33,332
Stock-based compensation expense	2,685		2,685
Foreign currency translation adjustments	11			11
Net loss	(10,407)				(10,407)
Ending balance at Mar. 31, 2021	$ 107,002	$ 26	$ 434,274	$ 52	$ (327,350)
Ending balance, shares at Mar. 31, 2021		25,834,208