Commitments and Contingencies (Details) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2019 USD ($)	Jun. 30, 2018 USD ($)	Jun. 30, 2019 USD ($) ft² LeaseAgreement	Jun. 30, 2018 USD ($)	Dec. 31, 2018 USD ($)
Operating Leases [Abstract]
Restricted cash	$ 1,525		$ 1,525		$ 1,436
Lease cost [Abstract]
Operating lease cost			501
Total lease cost			501
Maturities of operating lease liabilities [Abstract]
2019 (remaining six months)	546		546
2020	1,103		1,103
2021	894		894
2022	572		572
2023	73		73
Total future minimum lease payments	3,188		3,188
Less: Imputed interest	(342)		(342)
Present value of future minimum lease payments	2,846		2,846
Future annual minimum lease payment commitments [Abstract]
2019 (remaining six months)	987		987
2020	1,970		1,970
2021	1,907		1,907
2022	1,757		1,757
2023	1,618		1,618
Thereafter	20,144		20,144
Total	28,383		28,383
Operating lease assets and liabilities [Abstract]
Operating right-of-use assets	2,452		2,452		0
Operating current lease liabilities	913		913		0
Operating noncurrent lease liabilities	1,933		1,933		0
Present value of future minimum lease payments	$ 2,846		2,846
Cash paid for amounts included in the measurement of lease liabilities [Abstract]
Operating cash flows from operating leases			$ 542
Weighted-average remaining lease term - operating leases	3 years 1 month 6 days		3 years 1 month 6 days
Weighted-average discount rate - operating leases	7.77%		7.77%
Rent expense	$ 300	$ 200	$ 500	$ 400
Property Subject to Operating Lease [Member]
Operating Leases [Abstract]
Restricted cash	$ 1,000		$ 1,000		$ 1,400
NJ Lease Agreement [Member]
Operating Leases [Abstract]
Area of lease increased by amendment | ft²			10,000
Area of lease | ft²			102,000
Term of lease agreement	15 years		15 years
Number of options to renew lease agreement | LeaseAgreement			2
Term of renewal lease agreement	5 years		5 years
Estimated rent payments			$ 1,200
Percentage of annual increase in base rent			3.00%
Cash security deposit	$ 300		$ 300
Maturities of operating lease liabilities [Abstract]
Total future minimum lease payments	$ 26,500		$ 26,500