Consolidated Statements of Stockholders' Equity - USD ($) $ in Thousands	Total	Common stock	APIC	Accumulated Deficit
Beginning Balance at Dec. 31, 2018	$ 346,553	$ 10	$ 720,025	$ (373,482)
Balance (in shares) at Dec. 31, 2018		104,337,508
Increase (Decrease) in Stockholders' Equity
Net loss	(14,365)			(14,365)
Stock-based compensation	9,108		9,108
Shares issued in connection with employee stock plans, net of shares withheld for employee taxes	2,261		2,261
Shares issued in connection with employee stock plans, net of shares withheld for employee taxes (in shares)		781,538
Ending Balance at Mar. 31, 2019	339,867	$ 10	731,394	(391,537)
Balance (in shares) at Mar. 31, 2019		105,119,046
Beginning Balance at Dec. 31, 2019	$ 327,271	$ 11	759,322	(432,062)
Balance (in shares) at Dec. 31, 2019	106,865,830	106,865,830
Increase (Decrease) in Stockholders' Equity
Net loss	$ (10,669)			(10,669)
Stock-based compensation	6,559		6,559
Shares issued in connection with employee stock plans, net of shares withheld for employee taxes	(724)		(724)
Shares issued in connection with employee stock plans, net of shares withheld for employee taxes (in shares)		317,803
Ending Balance at Mar. 31, 2020	$ 322,437	$ 11	$ 765,157	$ (442,731)
Balance (in shares) at Mar. 31, 2020	107,183,633	107,183,633