Consolidated Statements of Changes in Stockholders' Equity - USD ($) $ in Thousands	Total	Common stock	Additional paid-in capital	Accumulated other comprehensive income (loss)	Accumulated deficit
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Effect of adoption of ASU | Accounting Standards Update 2016-09	$ 0		$ 2,616		$ (2,616)
Balance (in shares) at Dec. 31, 2016		26,821,762
Balance at Dec. 31, 2016	95,953	$ 27	189,335	$ (479)	(92,930)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Stock-based compensation expense	19,835		19,835
Common stock issued under employee stock plans, net (in shares)		1,324,400
Common stock issued under employee stock plans, net	12,083	$ 1	12,082
Unrealized gains (losses) on derivative instruments	642			642
Unrealized gains (losses) in available for sale securities	(27)			(27)
Net loss	(13,844)				(13,844)
Balance (in shares) at Dec. 31, 2017		28,146,162
Balance at Dec. 31, 2017	114,642	$ 28	223,868	136	(109,390)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Stock-based compensation expense	34,961		34,961
Common stock issued under employee stock plans, net (in shares)		1,430,718
Common stock issued under employee stock plans, net	8,114	$ 2	8,112
Unrealized gains (losses) on derivative instruments	(3,790)			(3,790)
Unrealized gains (losses) in available for sale securities	21			21
Net loss	(28,578)				(28,578)
Balance (in shares) at Dec. 31, 2018		29,576,880
Balance at Dec. 31, 2018	125,370	$ 30	266,941	(3,633)	(137,968)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Stock-based compensation expense	46,139		46,139
Common stock issued under employee stock plans, net (in shares)		1,006,431
Common stock issued under employee stock plans, net	(2,397)	$ 1	(2,398)
Unrealized gains (losses) on derivative instruments	3,158			3,158
Unrealized gains (losses) in available for sale securities	26			26
Net loss	(78,764)				(78,764)
Balance (in shares) at Dec. 31, 2019		30,583,311
Balance at Dec. 31, 2019	$ 93,532	$ 31	$ 310,682	$ (449)	$ (216,732)