Leases (Details) $ in Thousands	1 Months Ended	3 Months Ended
	Feb. 28, 2019 USD ($) ft²	Mar. 31, 2019 USD ($) item	Mar. 31, 2018 USD ($)	Dec. 31, 2018 USD ($)	Nov. 30, 2017 ft²
Lessee, Lease, Description [Line Items]
Rent expense			$ 276
Area leased, sublease agreement | ft²	21,056				33,019
Total renovation and improvement costs	$ 1,472	$ 143
Operating lease term (in years)	10 years
Number of lease financing arrangements | item		2
Finance lease term		4 years
Operating Leases:
Gross cost		$ 6,099		$ 5,951
Accumulated depreciation		(2,073)		(1,671)
Operating lease right-of-use assets		4,026		$ 4,280
Other current liabilities		373
Other liabilities		1,851
Total operating lease liabilities		2,224
Operating Leases
Lessee, Lease, Description [Line Items]
Total future total rent payments	$ 3,538
Operating Leases:
Gross cost		2,156
Accumulated depreciation		(88)
Operating lease right-of-use assets		$ 2,068
Financial position		us-gaap:OtherLiabilitiesCurrent
Financial position		us-gaap:OtherLiabilitiesNoncurrent