Summary of Significant Accounting Policies - Schedule of Reconciliation of Cash, Cash Equivalents, and Restricted Cash (Details) - USD ($) $ in Thousands	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Accounting Policies [Abstract]
Cash and cash equivalents	$ 23,587	$ 36,838	$ 22,088
Restricted cash included in prepaid expenses and other current assets	346
Restricted cash included in deposits and other long-term assets	466	847	847
Total cash, cash equivalents, and restricted cash as shown in the consolidated statements of cash flows	$ 24,399	$ 37,685	$ 22,935