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)	10,523			(1,509)	12,032
Issuance of common stock upon exercise of stock options (in shares)		316
Issuance of common stock upon exercise of stock options	1,347	$ 1	1,346
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)		597
Issuance of common stock for vested restricted stock units	0	$ 1	(1)
Tax withholding related to vesting of restricted stock units (in shares)		(96)
Tax withholding related to vesting of restricted stock units	(786)		(786)
Stock-based compensation costs	6,406		6,406
Ending Balance (in shares) at Jun. 30, 2020		49,547
Ending balance at Jun. 30, 2020	179,028	$ 124	590,800	(9,380)	(402,516)
Beginning balance (in shares) at Mar. 31, 2020		48,662
Beginning balance at Mar. 31, 2020	167,238	$ 122	585,198	(9,841)	(408,241)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Comprehensive income (loss)	6,186			461	5,725
Issuance of common stock upon exercise of stock options (in shares)		263
Issuance of common stock upon exercise of stock options	1,115	$ 1	1,114
Issuance of common stock under employee stock purchase plan (in shares)		204
Issuance of common stock under employee stock purchase plan	1,331		1,331
Issuance of common stock for vested restricted stock units (in shares)		483
Issuance of common stock for vested restricted stock units	0	$ 1	(1)
Tax withholding related to vesting of restricted stock units (in shares)		(65)
Tax withholding related to vesting of restricted stock units	(567)		(567)
Stock-based compensation costs	3,725		3,725
Ending Balance (in shares) at Jun. 30, 2020		49,547
Ending balance at Jun. 30, 2020	179,028	$ 124	590,800	(9,380)	(402,516)
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)	(28,436)			(312)	(28,124)
Issuance of common stock upon exercise of stock options (in shares)		398
Issuance of common stock upon exercise of stock options	2,155	$ 1	2,154
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)		1,305
Issuance of common stock for vested restricted stock units	0	$ 3	(3)
Tax withholding related to vesting of restricted stock units (in shares)		(315)
Tax withholding related to vesting of restricted stock units	(3,683)	$ (1)	(3,682)
Stock-based compensation costs	5,400		5,400
Ending Balance (in shares) at Jun. 30, 2021		52,080
Ending balance at Jun. 30, 2021	157,392	$ 130	602,877	1,423	(447,038)
Beginning balance (in shares) at Mar. 31, 2021		51,009
Beginning balance at Mar. 31, 2021	169,659	$ 128	599,744	(608)	(429,605)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Comprehensive income (loss)	(15,402)			2,031	(17,433)
Issuance of common stock upon exercise of stock options (in shares)		199
Issuance of common stock upon exercise of stock options	1,045		1,045
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)		802
Issuance of common stock for vested restricted stock units	0	$ 2	(2)
Tax withholding related to vesting of restricted stock units (in shares)		(165)
Tax withholding related to vesting of restricted stock units	(1,847)	$ (1)	(1,846)
Stock-based compensation costs	2,388		2,388
Ending Balance (in shares) at Jun. 30, 2021		52,080
Ending balance at Jun. 30, 2021	$ 157,392	$ 130	$ 602,877	$ 1,423	$ (447,038)