Accrued Expenses and Other Current Liabilities (Details)	1 Months Ended	3 Months Ended		9 Months Ended
	Jun. 30, 2020 employee	Sep. 30, 2021 USD ($)	Sep. 30, 2020 USD ($)	Sep. 30, 2021 USD ($)	Sep. 30, 2020 USD ($)	Dec. 31, 2020 USD ($)
Restructuring Cost and Reserve [Line Items]
Research and development		$ 1,100,000		$ 1,100,000		$ 512,000
Clinical		585,000		585,000		117,000
Professional fees		610,000		610,000		405,000
Employee-related		1,155,000		1,155,000		963,000
Severance-related		90,000		90,000		712,000
Other		422,000		422,000		232,000
Total accrued expenses and other current liabilities		3,962,000		3,962,000		$ 2,941,000
Severance costs		100,000	$ 200,000	600,000	$ 200,000
Severance-related charges
Restructuring Cost and Reserve [Line Items]
Number of employees given notice of termination | employee	5
Restructuring charges		0	400,000		1,100,000
Expected severance benefits to be paid		$ 100,000		$ 100,000
Severance-related charges | Research and development
Restructuring Cost and Reserve [Line Items]
Restructuring charges			$ 400,000		900,000
Severance-related charges | General and administrative
Restructuring Cost and Reserve [Line Items]
Restructuring charges					$ 200,000