Condenced Consolidated Statements of Stockholders' Equity - USD ($) shares in Thousands, $ in Thousands	Total	Common stock	Additional paid-in capital	Accumulated other comprehensive loss	Accumulated deficit
Beginning balance (in shares) at Dec. 31, 2018		46,378
Beginning balance at Dec. 31, 2018	$ 160,240	$ 116	$ 564,722	$ (7,126)	$ (397,472)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Comprehensive income (loss)	(11,154)			2,937	(14,091)
Issuance of common stock upon exercise of stock options (in shares)		48
Issuance of common stock upon exercise of stock options	166	$ 0	166
Issuance of common stock under employee stock purchase plan (in shares)		0
Issuance of common stock under employee stock purchase plan	0	$ 0	0
Issuance of common stock for vested restricted stock units (in shares)		42
Issuance of common stock for vested restricted stock units	0	$ 0	0
Tax withholding related to vesting of restricted stock units (in shares)		(13)
Tax withholding related to vesting of restricted stock units	(82)		(82)
Stock-based compensation costs	3,388		3,388
Ending Balance (in shares) at Mar. 31, 2019		46,455
Ending balance at Mar. 31, 2019	152,558	$ 116	568,194	(4,189)	(411,563)
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)	4,337			(1,970)	6,307
Issuance of common stock upon exercise of stock options (in shares)		52
Issuance of common stock upon exercise of stock options	231		231
Issuance of common stock under employee stock purchase plan (in shares)		0
Issuance of common stock under employee stock purchase plan	0	$ 0	0
Issuance of common stock for vested restricted stock units (in shares)		114
Issuance of common stock for vested restricted stock units	1	$ 1	0
Tax withholding related to vesting of restricted stock units (in shares)		(30)
Tax withholding related to vesting of restricted stock units	(219)		(219)
Stock-based compensation costs	2,682		2,682
Ending Balance (in shares) at Mar. 31, 2020		48,662
Ending balance at Mar. 31, 2020	$ 167,238	$ 122	$ 585,198	$ (9,841)	$ (408,241)