Leases (Details) $ in Thousands	1 Months Ended	3 Months Ended	6 Months Ended
	Feb. 28, 2019 USD ($) ft²	Jun. 30, 2018 USD ($)	Jun. 30, 2019 USD ($) item	Jun. 30, 2018 USD ($)	Dec. 31, 2018 USD ($)	Nov. 30, 2017 ft²
Lessee, Lease, Description [Line Items]
Rent expense		$ 201		$ 478
Area leased, sublease agreement | ft²	21,056					33,019
Total renovation and improvement costs	$ 1,472		$ 302
Number of lease financing arrangements | item			2
Finance lease term			4 years
Operating Leases:
Gross cost			$ 6,706		$ 5,951
Accumulated depreciation			(2,465)		(1,671)
Operating lease right-of-use assets			4,241		$ 4,280
Other current liabilities			488
Other liabilities			3,794
Total operating lease liabilities			4,282
Operating Leases
Lessee, Lease, Description [Line Items]
Total future total rent payments	$ 3,538
Operating Leases:
Gross cost			5,207
Accumulated depreciation			(177)
Operating lease right-of-use assets			$ 5,030
Financial position			us-gaap:OtherLiabilitiesCurrent
Financial position			us-gaap:OtherLiabilitiesNoncurrent