Leases - Lease Costs and Other Information (Details) - USD ($) $ in Thousands	3 Months Ended	9 Months Ended
	Sep. 30, 2019	Sep. 30, 2019
Lease Costs
Operating lease costs	$ 149	$ 464
Short-term lease costs	2	13
Variable lease costs	23	69
Total	174	546
Cash paid for amounts included in the measurement of lease liabilities:
Operating cash flows from operating leases	$ 145	$ 447