Consolidated Statement of Stockholders' Equity - USD ($) shares in Thousands, $ in Thousands	Total	Common Stock	Additional Paid-In Capital	Accumulated Other Comprehensive Income (Loss)	Accumulated Deficit
Balance at Dec. 31, 2018	$ 142,748	$ 59	$ 294,279	$ (93)	$ (151,497)
Balance (in shares) at Dec. 31, 2018		59,210
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Issuance of common stock upon exercise of stock options	982	$ 1	981
Issuance of common stock upon exercise of stock options (in shares)		216
Issuance of common stock upon vesting of restricted stock units	0	$ 0
Issuance of common stock upon vesting of restricted stock units (in shares)		211
Stock-based compensation	8,686		8,686
Other comprehensive income	174			174
Net loss	(1,924)				(1,924)
Balance at Mar. 31, 2019	150,666	$ 60	303,946	81	(153,421)
Balance (in shares) at Mar. 31, 2019		59,637
Balance at Dec. 31, 2019	196,458	$ 61	351,870	576	(156,049)
Balance (in shares) at Dec. 31, 2019		61,544
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Issuance of common stock upon exercise of stock options	2,597	$ 1	2,596
Issuance of common stock upon exercise of stock options (in shares)		160
Issuance of common stock upon vesting of restricted stock units	0	$ 0
Issuance of common stock upon vesting of restricted stock units (in shares)		288
Stock-based compensation	13,794		13,794
Other comprehensive income	1,054			1,054
Net loss	(7,437)				(7,437)
Balance at Mar. 31, 2020	$ 206,466	$ 62	$ 368,260	$ 1,630	$ (163,486)
Balance (in shares) at Mar. 31, 2020		61,992