Stockholders' Equity (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended
	Mar. 31, 2021	Mar. 31, 2020	Dec. 31, 2020
Shares
Number of common shares issued for each convertible Series A preferred stock	950,600
Deemed Dividends
Deemed dividends on Series A convertible preferred stock		$ 8,900
Series A Convertible Preferred Stock
Shares
Preferred stock, shares outstanding	4,753		4,753
Common Stock
Stock Options
Exercised (in shares)	55,030,000	59,978,000
Stock options
Stock option and incentive plans
Total compensation cost	$ 4,980	$ 1,875
Stock Options
Outstanding (in shares)	4,436,778
Outstanding, weighted-average exercise price (in dollars per share)	$ 11.97
Granted (in shares)	1,235,351
Granted (in dollars per share)	$ 13.33
Stock options | Research and development
Stock option and incentive plans
Total compensation cost	$ 1,190	729
Stock options | General and administrative
Stock option and incentive plans
Total compensation cost	3,790	1,146
Restricted stock
Stock option and incentive plans
Total compensation cost	$ 55	$ 1
Shares
Issued (in shares)	0	5,250
Outstanding (in shares)	22,000
Restricted stock | Minimum
Stock option and incentive plans
Vesting period	1 year
Restricted stock | Maximum
Stock option and incentive plans
Vesting period	3 years
Restricted stock | General and administrative
Stock option and incentive plans
Total compensation cost	$ 55	$ 1
2005 Plan
Stock option and incentive plans
Common stock reserved for issuance (in shares)	0
2005 Plan | Stock options
Stock Options
Outstanding (in shares)	6,565
2014 Plan
Stock option and incentive plans
Common stock reserved for issuance (in shares)	646,221
2014 Plan | Stock options
Stock Options
Outstanding (in shares)	3,386,335
Granted (in shares)	1,005,038
Equity Incentive Plan, Employee Inducments | Stock options
Stock Options
Outstanding (in shares)	1,043,878
Granted (in shares)	230,313