UNAUDITED CONDENSED CONSOLIDATED STATEMENTS OF STOCKHOLDERS' EQUITY - USD ($) shares in Thousands, $ in Thousands	Total	Common Stock	Additional Paid-In Capital	Retained Earnings	Accumulated Other Comprehensive (Loss)
Balance, beginning of period (in shares) at Dec. 31, 2018		78,526
Balance, beginning of period at Dec. 31, 2018	$ 621,531	$ 785	$ 123,205	$ 510,863	$ (13,322)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Repurchase of common stock (in shares)		(144)
Repurchase of common stock	(7,587)	$ (1)	(7,586)
Issuance of common stock for share-based compensation plans (in shares)		514
Issuance of common stock for share-based compensation plans	(14,838)	$ 5	(14,843)
Stock-based compensation	18,406		18,406
Cash dividends declared ($0.03 per share)	(2,367)			(2,367)
Other comprehensive income (loss)	2,001				2,001
Net (loss)	(28,717)			(28,717)
Balance, end of period (in shares) at Mar. 31, 2019		78,896
Balance, end of period at Mar. 31, 2019	$ 588,429	$ 789	119,182	479,779	(11,321)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Cash dividend declared (in dollars per share)	$ 0.03
Balance, beginning of period (in shares) at Dec. 31, 2018		78,526
Balance, beginning of period at Dec. 31, 2018	$ 621,531	$ 785	123,205	510,863	(13,322)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Other comprehensive income (loss)	(587)
Net (loss)	(91,351)
Balance, end of period (in shares) at Sep. 30, 2019		79,324
Balance, end of period at Sep. 30, 2019	528,832	$ 793	129,559	412,389	(13,909)
Balance, beginning of period (in shares) at Mar. 31, 2019		78,896
Balance, beginning of period at Mar. 31, 2019	588,429	$ 789	119,182	479,779	(11,321)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Repurchase of common stock (in shares)		(88)
Repurchase of common stock	(6,302)	$ (1)	(6,301)
Issuance of common stock for share-based compensation plans (in shares)		320
Issuance of common stock for share-based compensation plans	(11,214)	$ 3	(11,217)
Issuance of common stock under the employee stock purchase plan (in shares)		16
Issuance of common stock under the employee stock purchase plan	1,103		1,103
Stock-based compensation	20,113		20,113
Cash dividends declared ($0.03 per share)	(2,375)			(2,375)
Other comprehensive income (loss)	(171)				(171)
Net (loss)	(32,296)			(32,296)
Balance, end of period (in shares) at Jun. 30, 2019		79,144
Balance, end of period at Jun. 30, 2019	$ 557,287	$ 791	122,880	445,108	(11,492)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Cash dividend declared (in dollars per share)	$ 0.03
Repurchase of common stock (in shares)		(88)
Repurchase of common stock	$ (6,397)	$ (1)	(6,396)
Issuance of common stock for share-based compensation plans (in shares)		268
Issuance of common stock for share-based compensation plans	(8,801)	$ 3	(8,804)
Stock-based compensation	21,879		21,879
Cash dividends declared ($0.03 per share)	(2,381)			(2,381)
Other comprehensive income (loss)	(2,417)				(2,417)
Net (loss)	(30,338)			(30,338)
Balance, end of period (in shares) at Sep. 30, 2019		79,324
Balance, end of period at Sep. 30, 2019	$ 528,832	$ 793	129,559	412,389	(13,909)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Cash dividend declared (in dollars per share)	$ 0.03
Balance, beginning of period (in shares) at Dec. 31, 2019	79,599	79,599
Balance, beginning of period at Dec. 31, 2019	$ 539,010	$ 796	140,523	410,919	(13,228)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Equity component of convertible senior notes, net	61,604		61,604
Repurchase of common stock (in shares)		(87)
Repurchase of common stock	(6,000)	$ (1)	(5,999)
Issuance of common stock for share-based compensation plans (in shares)		564
Issuance of common stock for share-based compensation plans	(23,011)	$ 6	(23,017)
Stock-based compensation	23,199		23,199
Cash dividends declared ($0.03 per share)	(2,405)			(2,405)
Other comprehensive income (loss)	(414)				(414)
Net (loss)	(25,372)			(25,372)
Balance, end of period (in shares) at Mar. 31, 2020		80,076
Balance, end of period at Mar. 31, 2020	$ 566,611	$ 801	196,310	383,142	(13,642)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Cash dividend declared (in dollars per share)	$ 0.03
Balance, beginning of period (in shares) at Dec. 31, 2019	79,599	79,599
Balance, beginning of period at Dec. 31, 2019	$ 539,010	$ 796	140,523	410,919	(13,228)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Other comprehensive income (loss)	1,561
Net (loss)	$ (65,379)
Balance, end of period (in shares) at Sep. 30, 2020	80,697	80,697
Balance, end of period at Sep. 30, 2020	$ 529,322	$ 807	201,882	338,300	(11,667)
Balance, beginning of period (in shares) at Mar. 31, 2020		80,076
Balance, beginning of period at Mar. 31, 2020	566,611	$ 801	196,310	383,142	(13,642)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Repurchase of common stock (in shares)		(23)
Repurchase of common stock	(2,199)	$ 0	(2,199)
Issuance of common stock for share-based compensation plans (in shares)		349
Issuance of common stock for share-based compensation plans	(14,082)	$ 3	(14,085)
Issuance of common stock under the employee stock purchase plan (in shares)		18
Issuance of common stock under the employee stock purchase plan	1,403		1,403
Stock-based compensation	25,674		25,674
Cash dividends declared ($0.03 per share)	(2,413)			(2,413)
Other comprehensive income (loss)	2,028				2,028
Net (loss)	(20,740)			(20,740)
Balance, end of period (in shares) at Jun. 30, 2020		80,420
Balance, end of period at Jun. 30, 2020	$ 556,282	$ 804	207,103	359,989	(11,614)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Cash dividend declared (in dollars per share)	$ 0.03
Repurchase of common stock (in shares)		(94)
Repurchase of common stock	$ (10,629)	$ (1)	(10,628)
Issuance of common stock for share-based compensation plans (in shares)		371
Issuance of common stock for share-based compensation plans	(22,520)	$ 4	(22,524)
Stock-based compensation	27,931		27,931
Cash dividends declared ($0.03 per share)	(2,422)			(2,422)
Other comprehensive income (loss)	(53)				(53)
Net (loss)	$ (19,267)			(19,267)
Balance, end of period (in shares) at Sep. 30, 2020	80,697	80,697
Balance, end of period at Sep. 30, 2020	$ 529,322	$ 807	$ 201,882	$ 338,300	$ (11,667)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Cash dividend declared (in dollars per share)	$ 0.03