Debt Financing (Details) - USD ($)				6 Months Ended
	Apr. 17, 2020	Apr. 15, 2020	Jun. 19, 2019	Jun. 30, 2020	Jun. 30, 2019	Dec. 31, 2019
Line of Credit Facility [Line Items]
Proceeds from borrowings				$ 1,556,000	$ 0
Payment Protection Program Loan, CARES Act | U.S. Small Business Administration
Line of Credit Facility [Line Items]
Proceeds from borrowings	$ 1,556
Principal amount		$ 1,556
Interest rate		1.00%
Debt term		2 years
Cash Collateral Security Agreement | Standby Letters of Credit
Line of Credit Facility [Line Items]
Cash collateral, percentage of face amount of outstanding standby letters of credit			105.00%
Letters of credit, amount outstanding				2,860,000		$ 2,461,000
Restricted cash				$ 3,003,000		$ 2,584,000
Cash Collateral Security Agreement | Standby Letters of Credit | LIBOR
Line of Credit Facility [Line Items]
Basis spread on variable rate (as percent)			2.50%