Unaudited Condensed Consolidated Statement of Stockholder's Equity - USD ($) $ in Thousands	Total	Common Stock	Additional Paid-In Capital	Accumulated Other Comprehensive Income (Loss)	(Accumulated deficit) Retained Earnings
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Adoptions of ASU 2014-09 (ASC 606 Rev Rec), ASU 2016-16, and ASU 2018-02, net of tax	$ 8,593				$ 8,593
Beginning balance (in shares) at Dec. 31, 2017		31,320,000
Beginning balance at Dec. 31, 2017	730,485	$ 31	$ 603,137	$ (851)	128,168
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Change in unrealized gains and losses on available-for-sale securities, net of tax	(49)			(49)
Change in unrealized gains and losses on derivatives, net of tax	631			631
Net income	5,590				5,590
Stock-based compensation	$ 8,150		8,150
Repurchase of common stock (in shares)	0
Restricted stock unit withholdings (in shares)	(38,000)	(38,000)
Restricted stock unit withholdings	$ (2,271)				(2,271)
Issuance of common stock under stock-based compensation plans (in shares)		252,000
Issuance of common stock under stock-based compensation plans	4,590	$ 1	4,589
Ending balance (in shares) at Apr. 01, 2018		31,534,000
Ending balance at Apr. 01, 2018	755,719	$ 32	615,876	(269)	140,080
Beginning balance (in shares) at Dec. 31, 2018		31,562,000
Beginning balance at Dec. 31, 2018	627,552	$ 32	793,585	(15)	(166,050)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Change in unrealized gains and losses on available-for-sale securities, net of tax	12			12
Change in unrealized gains and losses on derivatives, net of tax	17			17
Net income	12,843				12,843
Stock-based compensation	$ 6,457		6,457
Repurchase of common stock (in shares)	(400,000)	(436,000)
Repurchase of common stock	$ (15,000)	$ 0			(15,000)
Restricted stock unit withholdings (in shares)	(89,000)	(89,000)
Restricted stock unit withholdings	$ (3,344)				(3,344)
Issuance of common stock under stock-based compensation plans (in shares)		430,000
Issuance of common stock under stock-based compensation plans	4,371	$ 0	4,371
Ending balance (in shares) at Mar. 31, 2019		31,467,000
Ending balance at Mar. 31, 2019	$ 632,908	$ 32	$ 804,413	$ 14	$ (171,551)