Condensed Consolidated Statements of Cash Flows (Unaudited) (Parenthetical) - USD ($) $ in Thousands	Mar. 31, 2019		Dec. 31, 2018	Mar. 31, 2018		Dec. 31, 2017
Statement Of Cash Flows [Abstract]
Cash and cash equivalents	$ 25,024		$ 31,213	$ 126,550
Restricted cash	50		50	175
Total cash and restricted cash	$ 25,074	[1]	$ 31,263	$ 126,725	[1]	$ 19,805

[1] The following table provides a reconciliation of cash and restricted cash to amounts reported within the condensed consolidated balance sheets: