Equity Transactions and Share-based Compensation (Tables)

6 Months Ended

Jun. 30, 2021

Share-based Payment Arrangement [Abstract]

Schedule of employee and non-employee share-based compensation expense recognized related to stock options, the ESPP and RSUs

Total share-based compensation expense recognized related to stock options, the ESPP and RSUs was as follows (in thousands): 

	Three Months Ended June 30,				Six Months Ended June 30,
	2021		2020		2021		2020
Research and development expense	$	1,765	$	725	$	3,142	$	1,465
General and administrative expense	1,347		666		2,554		1,252
Total share-based compensation expense	$	3,112	$	1,391	$	5,696	$	2,717