CONDENSED CONSOLIDATED STATEMENTS OF STOCKHOLDERS’ EQUITY - USD ($) $ in Thousands	Common Stock [Member]	Additional Paid-in Capital [Member]	Accumulated Other Comprehensive Loss [Member]	Accumulated Deficit [Member]	Total
Beginning balance at Dec. 31, 2018	$ 3	$ 184,158	$ (135)	$ (121,284)	$ 62,742
Beginning balance (in shares) at Dec. 31, 2018	29,442,065
Increase (Decrease) in Stockholders' Equity [Roll Forward]
ASC 842 adoption adjustment				248	248
Options exercised		26			26
Options exercised (in shares)	9,712
Employee stock purchase plan		544			544
Employee stock purchase plan (in shares)	129,815
Restricted stock units, net of taxes paid related to net settlement of equity awards		(85)			(85)
Restricted stock units, net of taxes paid related to net settlement of equity awards (in shares)	66,995
Stock-based compensation		1,075			1,075
Foreign currency translation adjustment			(128)		(128)
Net loss				(7,060)	(7,060)
Ending balance at Mar. 31, 2019	$ 3	185,718	(263)	(128,096)	57,362
Ending balance (in shares) at Mar. 31, 2019	29,648,587
Beginning balance at Dec. 31, 2018	$ 3	184,158	(135)	(121,284)	$ 62,742
Beginning balance (in shares) at Dec. 31, 2018	29,442,065
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Options exercised (in shares)					112,647
Ending balance at Dec. 31, 2019	$ 3	206,356	309	(147,892)	$ 58,776
Ending balance (in shares) at Dec. 31, 2019	30,268,685				30,268,685
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Options exercised		1,172			$ 1,172
Options exercised (in shares)	299,737				299,737
Employee stock purchase plan		777			$ 777
Employee stock purchase plan (in shares)	128,601
Restricted stock units, net of taxes paid related to net settlement of equity awards		(246)			(246)
Restricted stock units, net of taxes paid related to net settlement of equity awards (in shares)	119,142
Stock-based compensation		1,925			1,925
Foreign currency translation adjustment			(319)		(319)
Net loss				(11,015)	(11,015)
Ending balance at Mar. 31, 2020	$ 3	$ 209,984	$ (10)	$ (158,907)	$ 51,070
Ending balance (in shares) at Mar. 31, 2020	30,816,165				30,816,165