Leases - Overview (Details) $ in Thousands	1 Months Ended	3 Months Ended		9 Months Ended		18 Months Ended
	May 31, 2019 renewal_option	Sep. 30, 2020 USD ($)	Sep. 30, 2019 USD ($)	Sep. 30, 2020 USD ($)	Sep. 30, 2019 USD ($)	May 31, 2022 USD ($)	Dec. 31, 2019 USD ($)	Mar. 31, 2019 ft²	Jan. 15, 2019 USD ($)	Sep. 30, 2018 ft²
Lessee, Lease, Description [Line Items]
Operating lease right-of-use asset		$ 171		$ 171			$ 915		$ 1,800
Operating lease liability									$ 1,800
Minimum lease payments		$ 7,400		$ 7,400
Remaining lease term				2 months 12 days
Discount rate (as a percent)		8.00%		8.00%
Operating lease payments		$ 300	$ 300	$ 800	$ 800
Forecast
Lessee, Lease, Description [Line Items]
Operating lease income						$ 600
Leasehold improvements						$ 1,100
Office Space Sublease
Lessee, Lease, Description [Line Items]
Operating lease sublease land agreement | ft²								9,500		45,000
Number of renewal options | renewal_option	1
Renewal term	5 years