CONDENSED CONSOLIDATED STATEMENTS OF STOCKHOLDERS' EQUITY (Unaudited) - USD ($) shares in Thousands, $ in Thousands	Total	Follow-on Public Offering	Common Stock	Common Stock Follow-on Public Offering	Additional Paid-in Capital	Additional Paid-in Capital Follow-on Public Offering	Accumulated Deficit
Beginning Balance at Dec. 31, 2019	$ 62,140		$ 2		$ 116,162		$ (54,024)
Beginning Balance, Shares at Dec. 31, 2019			14,968
Stock-based compensation expense	9,749				9,749
Net income (loss)	(11,363)						(11,363)
Issuance of common stock upon follow-on public offering net of underwriting discounts and commissions and other offering costs		$ 45,789				$ 45,789
Issuance of common stock upon follow-on public offering net of underwriting discounts and commissions and other offerings costs, Shares				1,525
Issuance of shares upon vesting of restricted stock units, net of tax withholdings	(3,492)				(3,492)
Issuance of shares upon vesting of restricted stock units, net of tax withholdings, Shares			447
Ending Balance at Sep. 30, 2020	102,823		$ 2		168,208		(65,387)
Ending Balance, Shares at Sep. 30, 2020			16,940
Beginning Balance at Jun. 30, 2020	99,569		$ 2		164,287		(64,720)
Beginning Balance, Shares at Jun. 30, 2020			16,716
Stock-based compensation expense	3,919				3,919
Net income (loss)	(667)						(667)
Issuance of shares upon vesting of restricted stock units, net of tax withholdings	2				2
Issuance of shares upon vesting of restricted stock units, net of tax withholdings, Shares			224
Ending Balance at Sep. 30, 2020	102,823		$ 2		168,208		(65,387)
Ending Balance, Shares at Sep. 30, 2020			16,940
Beginning Balance at Dec. 31, 2020	$ 109,880		$ 2		173,274		(63,396)
Beginning Balance, Shares at Dec. 31, 2020	17,150		17,150
Stock-based compensation expense	$ 22,111				22,111
Net income (loss)	12,418						12,418
Issuance of common stock upon follow-on public offering net of underwriting discounts and commissions and other offering costs		$ 181,588				$ 181,588
Issuance of common stock upon follow-on public offering net of underwriting discounts and commissions and other offerings costs, Shares				1,500
Issuance of shares upon vesting of restricted stock units, net of tax withholdings, Shares			604
Ending Balance at Sep. 30, 2021	$ 325,997		$ 2		376,973		(50,978)
Ending Balance, Shares at Sep. 30, 2021	19,254		19,254
Beginning Balance at Jun. 30, 2021	$ 303,926		$ 2		368,862		(64,938)
Beginning Balance, Shares at Jun. 30, 2021			19,061
Stock-based compensation expense	8,111				8,111
Net income (loss)	13,960						13,960
Issuance of shares upon vesting of restricted stock units, net of tax withholdings, Shares			193
Ending Balance at Sep. 30, 2021	$ 325,997		$ 2		$ 376,973		$ (50,978)
Ending Balance, Shares at Sep. 30, 2021	19,254		19,254