Summary of Significant Accounting Policies (Details) - USD ($) $ in Thousands	Sep. 30, 2019	Dec. 31, 2018	Sep. 30, 2018	Dec. 31, 2017
Restricted Cash and Cash Equivalents Items [Line Items]
Balance of total restricted cash	$ 2,482
Cash and cash equivalents	12,850	$ 12,039
Restricted cash included in current assets	988	6,020
Restricted cash included in long-term assets	1,494	0
Total cash, cash equivalents, and restricted cash shown in the Consolidated Statements of Cash Flows	15,332	$ 18,059	$ 10,718	$ 14,386
Restricted Until Maturity Date
Restricted Cash and Cash Equivalents Items [Line Items]
Balance of total restricted cash	988
Restricted Until Expiration of Agreement December 2020
Restricted Cash and Cash Equivalents Items [Line Items]
Balance of total restricted cash	$ 1,494