Condensed Statements of Stockholders' Equity (Unaudited) - USD ($) shares in Thousands, $ in Thousands	Total	Common Stock	Additional Paid- In Capital	Accumulated Other Comprehensive Income (Loss)	Accumulated Deficit
Beginning balance at Dec. 31, 2019	$ 218,781	$ 5	$ 431,322	$ 331	$ (212,877)
Beginning balance (in shares) at Dec. 31, 2019		45,384
Share-based compensation expense	3,153		3,153
Issuance of common stock from exercise of options	247		247
Issuance of common stock from exercise of options (in shares)		46
Other comprehensive income (loss)	230			230
Net loss	(19,210)				(19,210)
Ending balance at Mar. 31, 2020	203,201	$ 5	434,722	561	(232,087)
Ending balance (in shares) at Mar. 31, 2020		45,430
Beginning balance at Dec. 31, 2020	610,905	$ 7	913,354	46	(302,502)
Beginning balance (in shares) at Dec. 31, 2020		66,194
Share-based compensation expense	5,075		5,075
Issuance of common stock from exercise of options	829		829
Issuance of common stock from exercise of options (in shares)		69
Other comprehensive income (loss)	(128)			(128)
Net loss	(30,694)				(30,694)
Ending balance at Mar. 31, 2021	$ 585,987	$ 7	$ 919,258	$ (82)	$ (333,196)
Ending balance (in shares) at Mar. 31, 2021		66,263