Statement of Stockholders' Equity - USD ($) $ in Thousands	Common Stock	Additional Paid-in Capital	Accumulated Other Comprehensive Income (Loss)	Accumulated Deficit	Total
Balance at Dec. 31, 2018	$ 563	$ 845,366	$ (971)	$ (323,277)	$ 521,681
Balance (in shares) at Dec. 31, 2018	56,279,542
Increase (Decrease) in Stockholders' Equity
Issuance of common stock upon exercise of stock awards	$ 1	666			667
Issuance of common stock upon exercise of stock awards (in shares)	58,536
Issuance of restricted stock units (in shares)	11,311
Comprehensive income (loss)			1,316	80,045	81,361
Stock-based compensation expense		5,856			5,856
Balance at Mar. 31, 2019	$ 564	851,888	345	(243,232)	609,565
Balance (in shares) at Mar. 31, 2019	56,349,389
Balance at Dec. 31, 2018	$ 563	845,366	(971)	(323,277)	521,681
Balance (in shares) at Dec. 31, 2018	56,279,542
Increase (Decrease) in Stockholders' Equity
Comprehensive income (loss)					66,612
Balance at Jun. 30, 2019	$ 565	865,163	1,629	(259,266)	608,091
Balance (in shares) at Jun. 30, 2019	56,529,398
Balance at Mar. 31, 2019	$ 564	851,888	345	(243,232)	609,565
Balance (in shares) at Mar. 31, 2019	56,349,389
Increase (Decrease) in Stockholders' Equity
Issuance of common stock upon exercise of stock awards	$ 1	3,238			3,239
Issuance of common stock upon exercise of stock awards (in shares)	143,504
Issuance of common stock under the Employee Stock Purchase Plan		734			734
Issuance of common stock under the Employee Stock Purchase Plan (in shares)	36,505
Comprehensive income (loss)			1,284	(16,034)	(14,750)
Stock-based compensation expense		9,303			9,303
Balance at Jun. 30, 2019	$ 565	865,163	1,629	(259,266)	608,091
Balance (in shares) at Jun. 30, 2019	56,529,398
Balance at Dec. 31, 2019	$ 569	887,873	1,161	(296,402)	593,201
Balance (in shares) at Dec. 31, 2019	56,902,301
Increase (Decrease) in Stockholders' Equity
Issuance of common stock upon exercise of stock awards	$ 1	1,470			1,471
Issuance of common stock upon exercise of stock awards (in shares)	79,930
Issuance of restricted stock units (in shares)	19,022
Comprehensive income (loss)			(105)	(8,074)	(8,179)
Stock-based compensation expense		6,512			6,512
Balance at Mar. 31, 2020	$ 570	895,855	1,056	(304,476)	593,005
Balance (in shares) at Mar. 31, 2020	57,001,253
Balance at Dec. 31, 2019	$ 569	887,873	1,161	(296,402)	593,201
Balance (in shares) at Dec. 31, 2019	56,902,301
Increase (Decrease) in Stockholders' Equity
Comprehensive income (loss)					(42,770)
Balance at Jun. 30, 2020	$ 572	908,084	1,483	(339,494)	570,645
Balance (in shares) at Jun. 30, 2020	57,214,253
Balance at Mar. 31, 2020	$ 570	895,855	1,056	(304,476)	593,005
Balance (in shares) at Mar. 31, 2020	57,001,253
Increase (Decrease) in Stockholders' Equity
Issuance of common stock upon exercise of stock awards	$ 2	3,273			3,275
Issuance of common stock upon exercise of stock awards (in shares)	181,856
Issuance of common stock under the Employee Stock Purchase Plan		725			725
Issuance of common stock under the Employee Stock Purchase Plan (in shares)	28,344
Issuance of restricted stock units (in shares)	2,800
Comprehensive income (loss)			427	(35,018)	(34,591)
Stock-based compensation expense		8,231			8,231
Balance at Jun. 30, 2020	$ 572	$ 908,084	$ 1,483	$ (339,494)	$ 570,645
Balance (in shares) at Jun. 30, 2020	57,214,253