CONSOLIDATED STATEMENTS OF SHAREHOLDERS' EQUITY - USD ($) $ in Thousands	Total	Common Stock	Accumulated Other Comprehensive Gain (loss)	Accumulated Deficit
Beginning balance (in shares) at Dec. 31, 2019		44,864,000
Beginning balance at Dec. 31, 2019	$ 111,091	$ 489,749	$ 21	$ (378,679)
Increase (Decrease) in Shareholders' Equity
Net (loss) income	2,864			2,864
Stock-based compensation expense	13,843	$ 13,843
Stock option exercises (in shares)		790,000
Stock option exercises	5,582	$ 5,582
Shares issued under the Employee Stock Purchase Plan (in shares)		117,000
Shares issued under the Employee Stock Purchase Plan	1,050	$ 1,050
Issuance of stock for restricted stock unit vesting (shares)		47,000
Restricted stock withheld for employee tax remittance (in shares)		(14,000)
Restricted stock withheld for employee tax remittance	(163)	$ (163)
Unrealized loss on investments	(7)		(7)
Ending balance (in shares) at Dec. 31, 2020		45,804,000
Ending balance at Dec. 31, 2020	134,260	$ 510,061	14	(375,815)
Increase (Decrease) in Shareholders' Equity
Net (loss) income	(7,471)			(7,471)
Stock-based compensation expense	34,322	$ 34,322
Stock option exercises (in shares)		968,000
Stock option exercises	9,928	$ 9,928
Shares issued under the Employee Stock Purchase Plan (in shares)		43,000
Shares issued under the Employee Stock Purchase Plan	1,256	$ 1,256
Issuance of stock for restricted stock unit vesting (shares)		96,000
Restricted stock withheld for employee tax remittance (in shares)		(31,000)
Restricted stock withheld for employee tax remittance	(1,665)	$ (1,665)
Unrealized loss on investments	$ (168)		(168)
Ending balance (in shares) at Dec. 31, 2021	46,880,000	46,880,000
Ending balance at Dec. 31, 2021	$ 170,462	$ 553,902	(154)	(383,286)
Increase (Decrease) in Shareholders' Equity
Net (loss) income	(16,709)			(16,709)
Stock-based compensation expense	$ 37,183	$ 37,183
Stock option exercises (in shares)	234,707	234,000
Stock option exercises	$ 2,401	$ 2,401
Shares issued under the Employee Stock Purchase Plan (in shares)		49,000
Shares issued under the Employee Stock Purchase Plan	1,251	$ 1,251
Issuance of stock for restricted stock unit vesting (shares)		134,000
Restricted stock withheld for employee tax remittance (in shares)		(44,000)
Restricted stock withheld for employee tax remittance	(1,492)	$ (1,492)
Unrealized loss on investments	$ (824)		(824)
Ending balance (in shares) at Dec. 31, 2022	47,253,000	47,253,000
Ending balance at Dec. 31, 2022	$ 192,272	$ 593,245	$ (978)	$ (399,995)