CONSOLIDATED STATEMENTS OF STOCKHOLDERS' EQUITY (DEFICIT) - USD ($)	Common Stock	Additional Paid-In Capital	Accumulated Deficit	Accumulated Other Comprehensive Income	Total
Balance as of beginning of the period at Dec. 31, 2018	$ 70,000	$ 1,434,780,000	$ (408,661,000)	$ (13,070,000)	$ 1,013,119,000
Balance as of beginning of the period (in shares) at Dec. 31, 2018	70,516,249
Stockholders' Equity (Deficit)
Exercise of stock options	$ 1,000	8,853,000	0	0	8,854,000
Exercise of stock options (in shares)	564,102
Issuance of common stock upon vesting of restricted stock units	$ 0	0	0	0	0
Issuance of common stock upon vesting of restricted stock units (in shares)	383,060
Stock-based compensation	$ 0	13,523,000	0	0	13,523,000
Other comprehensive income (loss), net of tax	0	0	0	(3,788,000)	(3,788,000)
Net loss	0	0	(30,150,000)	0	(30,150,000)
Balance as of end of the period at Mar. 31, 2019	$ 71,000	1,457,156,000	(438,811,000)	(16,858,000)	1,001,558,000
Balance as of end of the period (in shares) at Mar. 31, 2019	71,463,411
Balance as of beginning of the period at Dec. 31, 2018	$ 70,000	1,434,780,000	(408,661,000)	(13,070,000)	1,013,119,000
Balance as of beginning of the period (in shares) at Dec. 31, 2018	70,516,249
Balance as of end of the period at Dec. 31, 2019	$ 73,000	1,538,716,000	(507,525,000)	(17,239,000)	1,014,025,000
Balance as of end of the period (in shares) at Dec. 31, 2019	72,761,941
Stockholders' Equity (Deficit)
Exercise of stock options	$ 0	14,830,000	0	0	14,830,000
Exercise of stock options (in shares)	671,279
Issuance of common stock upon vesting of restricted stock units	$ 1,000	(1,000)	0	0	0
Issuance of common stock upon vesting of restricted stock units (in shares)	642,411
Issuance of common stock for Convertible Notes	$ 0	58,000	0	0	58,000
Issuance of common stock for Convertible Notes (in shares)	655
Stock-based compensation	$ 0	18,421,000	0	0	18,421,000
Other comprehensive income (loss), net of tax	0	0	0	(17,554,000)	(17,554,000)
Net loss	0	0	(29,603,000)	0	(29,603,000)
Balance as of end of the period at Mar. 31, 2020	$ 74,000	$ 1,572,024,000	$ (537,128,000)	$ (34,793,000)	$ 1,000,177,000
Balance as of end of the period (in shares) at Mar. 31, 2020	74,076,286