Borrowing Arrangements (Details) - USD ($)	9 Months Ended
	Sep. 30, 2021	Jan. 31, 2021	Dec. 31, 2020	Sep. 30, 2020	Mar. 12, 2020	Feb. 29, 2020	Nov. 30, 2019	Nov. 27, 2019
Line of Credit Facility [Line Items]
Restricted cash	$ 856,000		$ 1,006,000
Series C Preferred Stock Warrants
Line of Credit Facility [Line Items]
Class of warrant or right, number securities called by warrants or rights (in shares)					89,747	1,341,865	89,747	89,747
Class of warrant or right, exercise price of warrants or rights (in dollars per share)					$ 7.67			$ 7.67
Series D Preferred Stock Warrants
Line of Credit Facility [Line Items]
Class of warrant or right, number securities called by warrants or rights (in shares)					98,723
Class of warrant or right, exercise price of warrants or rights (in dollars per share)					$ 6.96
Business Credit Card | Line of Credit
Line of Credit Facility [Line Items]
Debt instrument, covenant, required collateral amount		$ 200,000
Capital Agreement, 2019 | Notes Payable, Other Payables
Line of Credit Facility [Line Items]
Debt instrument, maximum borrowing capacity								$ 50,000,000
Debt, long-term and short-term, combined amount			$ 0
Capital Agreement, 2019, Tranche One | Notes Payable, Other Payables
Line of Credit Facility [Line Items]
Debt instrument, maximum borrowing capacity								25,000,000
Capital Agreement, 2019, Tranche Two | Notes Payable, Other Payables
Line of Credit Facility [Line Items]
Debt instrument, maximum borrowing capacity								25,000,000
Letter of Credit | Line of Credit
Line of Credit Facility [Line Items]
Line of credit facility, maximum borrowing capacity				$ 3,500,000				$ 2,000,000
Proceeds from issuance of debt	800,000
Debt instrument, covenant, required collateral amount	800,000
Restricted cash	$ 800,000