Commitments and Contingencies - Schedule of Lease Costs and Weighted-Average Assumptions Used in Determining its Lease Assets and Lease Liabilities (Details) $ in Thousands	3 Months Ended	6 Months Ended
	Jun. 30, 2019 USD ($)	Jun. 30, 2019 USD ($)
Commitments And Contingencies Disclosure [Abstract]
Operating lease cost	$ 200	$ 331
Cash paid for operating leases	$ 200	345
Lease assets obtained in exchange for operating lease liabilities		$ 839
Weighted average remaining term for operating leases	10 months 17 days	10 months 17 days
Weighted average discount rate for operating leases	6.00%	6.00%