CONSOLIDATED STATEMENTS OF STOCKHOLDERS' EQUITY - USD ($) $ in Thousands		Total		IPO	[1]	Private placement	[1]	Common Stock	Common Stock IPO	Common Stock Private placement	Additional Paid‑In Capital	Additional Paid‑In Capital IPO	Additional Paid‑In Capital Private placement	Accumulated Other Comprehensive Loss	Accumulated Deficit
Beginning balance (in shares) at Dec. 31, 2019								102,843,612
Beginning balance at Dec. 31, 2019		$ 500,722	[1]					$ 103			$ 568,756			$ 0	$ (68,137)	[1]
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Issuance of common stock (shares)									13,500,000	85,880
Issuance of common stock				$ 318,993		$ 2,233			$ 14			$ 318,979	$ 2,233
Exercise of stock options (in shares)								33,792
Exercise of stock options		185	[1]								185
Share‑based compensation		3,903	[1]								3,903
Foreign currency translation adjustments	[1]	0
Net loss		(15,718)	[2]												(15,718)	[1]
Ending balance (in shares) at Sep. 30, 2020								116,463,284
Ending balance at Sep. 30, 2020		810,318	[1]					$ 117			894,056			0	(83,855)	[1]
Beginning balance (in shares) at Jun. 30, 2020								102,862,404
Beginning balance at Jun. 30, 2020		492,070	[1]					$ 103			570,434			0	(78,467)	[1]
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Issuance of common stock (shares)									13,500,000	85,880
Issuance of common stock				$ 318,993		$ 2,233			$ 14			$ 318,979	$ 2,233
Exercise of stock options (in shares)								15,000
Exercise of stock options		82	[1]								82
Share‑based compensation		2,328	[1]								2,328
Foreign currency translation adjustments	[1]	0
Net loss	[1]	(5,388)													(5,388)
Ending balance (in shares) at Sep. 30, 2020								116,463,284
Ending balance at Sep. 30, 2020		810,318	[1]					$ 117			894,056			0	(83,855)	[1]
Beginning balance (in shares) at Dec. 31, 2020								116,992,472
Beginning balance at Dec. 31, 2020		811,014	[1]					$ 117			903,116			0	(92,219)	[1]
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Exercise of stock options (in shares)								1,526,856
Exercise of stock options		8,570	[1]					$ 2			8,568
Vesting of restricted stock units (in shares)								507,776
Share‑based compensation		22,774	[1]								22,774
Purchase of capped calls		(36,030)	[1]								(36,030)
Foreign currency translation adjustments		(8,120)	[1]											(8,120)
Net loss	[1]	(51,439)													(51,439)
Ending balance (in shares) at Sep. 30, 2021								119,027,104
Ending balance at Sep. 30, 2021		746,769	[1]					$ 119			898,428			(8,120)	(143,658)	[1]
Beginning balance (in shares) at Jun. 30, 2021								118,249,912
Beginning balance at Jun. 30, 2021		803,959	[1]					$ 118			917,116			0	(113,275)	[1]
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Exercise of stock options (in shares)								269,416
Exercise of stock options		1,507	[1]					$ 1			1,506
Vesting of restricted stock units (in shares)								507,776
Share‑based compensation		15,836	[1]								15,836
Purchase of capped calls		(36,030)	[1]								(36,030)
Foreign currency translation adjustments		(8,120)	[1]											(8,120)
Net loss	[1]	(30,383)													(30,383)
Ending balance (in shares) at Sep. 30, 2021								119,027,104
Ending balance at Sep. 30, 2021		$ 746,769	[1]					$ 119			$ 898,428			$ (8,120)	$ (143,658)	[1]

[1] Certain prior period amounts have been revised to correct immaterial errors. See Note 1 for more information.

[2] Certain prior period amounts have been revised to correct immaterial errors. See Note 1 for more information.