Commitments and Contingencies - Additional Lease Disclosures and Other Commitments and Contingencies (Details) - USD ($)	3 Months Ended
	Mar. 31, 2019	Dec. 31, 2018
Operating Cash Flows Supplemental Information:
Cash paid for amounts included in the measurement of the operating lease liabilities	$ 111,000
Right-of-use assets obtained in exchange for operating lease obligations	2,021,000
Future payments of operating lease liabilities, ASC 842
Remainder of 2019	404,000
2020	507,000
2021	515,000
2022	522,000
2023	533,000
Total future minimum lease payments	2,481,000
Less imputed interest	(504,000)
Present value of operating lease liabilities	1,977,000
Future minimum expected lease payments under non-cancelable operating leases, ASC 840
2019		$ 515,000
2020		507,000
2021		515,000
Total lease payments		$ 1,537,000
Other Commitments and Contingencies
Contingent liabilities	$ 0