Consolidated Statements of Changes in Stockholders’ Equity - USD ($) $ in Thousands	Total	Common Stock	Additional Paid-in Capital	Accumulated Deficit	Accumulated Other Comprehensive Income
Beginning balance (in shares) at Dec. 31, 2018		90,151,341
Beginning balance at Dec. 31, 2018	$ 371,938	$ 90	$ 542,829	$ (170,981)	$ 0
Increase (Decrease) in Stockholders' Equity
Issuance of common stock pursuant to exercise of stock options (in shares)		679,495
Issuance of common stock pursuant to exercise of stock options	3,732	$ 1	3,731
Issuance of common stock pursuant to settlement of restricted stock units (in shares)		139,889
Issuance of common stock pursuant to settlement of restricted stock units	0
Common stock surrendered for employees' tax liability upon settlement of restricted stock units (in shares)		(44,476)
Common stock surrendered for employees' tax liability upon settlement of restricted stock units	(818)		(818)
Stock-based compensation	6,676		6,676
Other comprehensive income	1				1
Net loss	(67,180)			(67,180)
Ending balance (in shares) at Mar. 31, 2019		90,926,249
Ending balance at Mar. 31, 2019	$ 314,349	$ 91	552,418	(238,160)	1
Beginning balance (in shares) at Dec. 31, 2019	93,001,597	93,001,597
Beginning balance at Dec. 31, 2019	$ 331,446	$ 93	583,097	(251,786)	42
Increase (Decrease) in Stockholders' Equity
Issuance of common stock pursuant to exercise of stock options (in shares)	738,398	738,398
Issuance of common stock pursuant to exercise of stock options	$ 3,916	$ 1	3,915
Issuance of common stock pursuant to settlement of restricted stock units (in shares)		320,440
Issuance of common stock pursuant to settlement of restricted stock units	0
Common stock surrendered for employees' tax liability upon settlement of restricted stock units (in shares)		(102,661)
Common stock surrendered for employees' tax liability upon settlement of restricted stock units	(3,307)		(3,307)
Stock-based compensation	7,715		7,715
Other comprehensive income	533				533
Net loss	$ (60,117)			(60,117)
Ending balance (in shares) at Mar. 31, 2020	93,957,774	93,957,774
Ending balance at Mar. 31, 2020	$ 280,186	$ 94	$ 591,420	$ (311,903)	$ 575