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 investments, 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
Restricted stock unit withholdings (in shares)		(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, 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]
Restricted stock unit withholdings (in shares)	(100,000)
Ending balance (in shares) at Jul. 01, 2018		31,781,000
Beginning balance (in shares) at Apr. 01, 2018		31,534,000
Beginning balance at Apr. 01, 2018	$ 755,719	$ 32	615,876	(269)	140,080
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Change in unrealized gains and losses on available-for-sale investments, net of tax	53			53
Change in unrealized gains and losses on derivatives, net of tax	109			109
Net income	(5,230)				(5,230)
Stock-based compensation	8,970		8,970
Restricted stock unit withholdings (in shares)		(85,000)
Restricted stock unit withholdings	(4,897)				(4,897)
Issuance of common stock under stock-based compensation plans (in shares)		332,000
Issuance of common stock under stock-based compensation plans	1,012	$ 0	1,012
Ending balance (in shares) at Jul. 01, 2018		31,781,000
Stockholders' Equity, Including Portion Attributable to Noncontrolling Interest	755,736	$ 32	625,858	(107)	129,953
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 investments, 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)		(436,000)
Repurchase of common stock	(15,000)	$ 0			(15,000)
Restricted stock unit withholdings (in shares)		(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)
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]
Repurchase of common stock (in shares)	(1,000,000.0)
Repurchase of common stock	$ (32,000)
Restricted stock unit withholdings (in shares)	(200,000)
Ending balance (in shares) at Jun. 30, 2019		31,110,000
Ending balance at Jun. 30, 2019	$ 622,072	$ 31	812,034	12	(190,005)
Beginning balance (in shares) at Mar. 31, 2019		31,467,000
Beginning balance at Mar. 31, 2019	632,908	$ 32	804,413	14	(171,551)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Change in unrealized gains and losses on available-for-sale investments, net of tax	0			0
Change in unrealized gains and losses on derivatives, net of tax	(2)			(2)
Net income	839				839
Stock-based compensation	6,739		6,739
Repurchase of common stock (in shares)		(570,000)
Repurchase of common stock	(16,980)	$ (1)			(16,979)
Restricted stock unit withholdings (in shares)		(79,000)
Restricted stock unit withholdings	(2,314)				(2,314)
Issuance of common stock under stock-based compensation plans (in shares)		292,000
Issuance of common stock under stock-based compensation plans	882	$ 0	882
Ending balance (in shares) at Jun. 30, 2019		31,110,000
Ending balance at Jun. 30, 2019	$ 622,072	$ 31	$ 812,034	$ 12	$ (190,005)