Unaudited Consolidated Statements of Changes in Stockholders' Equity - USD ($) $ in Thousands	Total	Common stock	Additional paid-in capital	Accumulated other comprehensive income	Accumulated deficit
Beginning balance (in shares) at Dec. 31, 2019		91,749,933
Beginning balance at Dec. 31, 2019	$ 93,532	$ 92	$ 310,621	$ (449)	$ (216,732)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Stock-based compensation expense	12,883		12,883
Common stock issued under employee stock plans, net (in shares)		2,648,877
Common stock issued under employee stock plans, net	4,316	$ 2	4,314
Unrealized income on derivative instruments	545			545
Unrealized income on available for sale securities	195			195
Net loss	(31,430)				(31,430)
Ending balance (in shares) at Mar. 31, 2020		94,398,810
Ending balance at Mar. 31, 2020	80,041	$ 94	327,818	291	(248,162)
Beginning balance (in shares) at Dec. 31, 2020		95,456,862
Beginning balance at Dec. 31, 2020	94,071	$ 95	395,347	9,371	(310,742)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Issuance of Common stock in connection with follow-on offering, net of issuance costs of $17,466 (in shares)		7,961,538
Issuance of Common stock in connection with follow-on offering, net of issuance costs of $17,466	500,034	$ 8	500,026
Stock-based compensation expense	21,379		21,379
Common stock issued under employee stock plans, net (in shares)		2,728,995
Common stock issued under employee stock plans, net	3,942	$ 3	3,939
Unrealized income on derivative instruments	(5,185)			(5,185)
Unrealized income on available for sale securities	5			5
Net loss	(35,656)				(35,656)
Ending balance (in shares) at Mar. 31, 2021		106,147,395
Ending balance at Mar. 31, 2021	$ 578,590	$ 106	$ 920,691	$ 4,191	$ (346,398)