CONDENSED CONSOLIDATED STATEMENTS OF STOCKHOLDERS’ EQUITY (Unaudited) - USD ($) shares in Thousands, $ in Thousands	Total	Common stock	Additional paid-in capital	Accumulated other comprehensive income (loss)	Accumulated deficit
Beginning balance (in shares) at Dec. 31, 2019		48,526
Beginning balance at Dec. 31, 2019	$ 160,206	$ 121	$ 582,504	$ (7,871)	$ (414,548)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Comprehensive income (loss)	10,937			3,808	7,129
Issuance of common stock upon exercise of stock options (in shares)		322
Issuance of common stock upon exercise of stock options	1,387	$ 1	1,386
Issuance of common stock under employee stock purchase plan (in shares)		204
Issuance of common stock under employee stock purchase plan	1,332	$ 1	1,331
Issuance of common stock for vested restricted stock units (in shares)		1,288
Issuance of common stock for vested restricted stock units	0	$ 3	(3)
Tax withholding related to vesting of restricted stock units (in shares)		(202)
Tax withholding related to vesting of restricted stock units	(1,722)	$ (1)	(1,721)
Stock-based compensation costs	9,378		9,378
Ending Balance (in shares) at Sep. 30, 2020		50,138
Ending balance at Sep. 30, 2020	181,518	$ 125	592,875	(4,063)	(407,419)
Beginning balance (in shares) at Jun. 30, 2020		49,547
Beginning balance at Jun. 30, 2020	179,028	$ 124	590,800	(9,380)	(402,516)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Comprehensive income (loss)	414			5,317	(4,903)
Issuance of common stock upon exercise of stock options (in shares)		7
Issuance of common stock upon exercise of stock options	40		40
Issuance of common stock for vested restricted stock units (in shares)		690
Issuance of common stock for vested restricted stock units	0	$ 2	(2)
Tax withholding related to vesting of restricted stock units (in shares)		(106)
Tax withholding related to vesting of restricted stock units	(936)	$ (1)	(935)
Stock-based compensation costs	2,972		2,972
Ending Balance (in shares) at Sep. 30, 2020		50,138
Ending balance at Sep. 30, 2020	181,518	$ 125	592,875	(4,063)	(407,419)
Beginning balance (in shares) at Dec. 31, 2020		50,457
Beginning balance at Dec. 31, 2020	180,407	$ 126	597,460	1,735	(418,914)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Comprehensive income (loss)	(30,539)			(555)	(29,984)
Issuance of common stock upon exercise of stock options (in shares)		529
Issuance of common stock upon exercise of stock options	2,967	$ 1	2,966
Issuance of common stock under employee stock purchase plan (in shares)		235
Issuance of common stock under employee stock purchase plan	1,549	$ 1	1,548
Issuance of common stock for vested restricted stock units (in shares)		1,883
Issuance of common stock for vested restricted stock units	0	$ 5	(5)
Tax withholding related to vesting of restricted stock units (in shares)		(445)
Tax withholding related to vesting of restricted stock units	(4,952)	$ (1)	(4,951)
Stock-based compensation costs	7,709		7,709
Ending Balance (in shares) at Sep. 30, 2021		52,659
Ending balance at Sep. 30, 2021	157,141	$ 132	604,727	1,180	(448,898)
Beginning balance (in shares) at Jun. 30, 2021		52,080
Beginning balance at Jun. 30, 2021	157,392	$ 130	602,877	1,423	(447,038)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Comprehensive income (loss)	(2,103)			(243)	(1,860)
Issuance of common stock upon exercise of stock options (in shares)		131
Issuance of common stock upon exercise of stock options	812		812
Issuance of common stock for vested restricted stock units (in shares)		578
Issuance of common stock for vested restricted stock units	0	$ 2	(2)
Tax withholding related to vesting of restricted stock units (in shares)		(130)
Tax withholding related to vesting of restricted stock units	(1,269)		(1,269)
Stock-based compensation costs	2,309		2,309
Ending Balance (in shares) at Sep. 30, 2021		52,659
Ending balance at Sep. 30, 2021	$ 157,141	$ 132	$ 604,727	$ 1,180	$ (448,898)