Consolidated Statements of Cash Flows (Parenthetical) - USD ($) $ in Thousands	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Statement Of Cash Flows [Abstract]
Cash	$ 164	$ 170	$ 3,696
Restricted cash included in other long-term assets			$ 395
Restricted Cash and Cash Equivalents, Noncurrent, Asset, Statement of Financial Position [Extensible List]	us-gaap:OtherAssetsNoncurrent	us-gaap:OtherAssetsNoncurrent	us-gaap:OtherAssetsNoncurrent
Total cash and restricted cash	$ 164	$ 170	$ 4,091