Stockholder Rights Plan (Details) - USD ($) $ / shares in Units, $ in Thousands		12 Months Ended
	Mar. 27, 2018	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Equity [Abstract]
Redemption price per share (in dollars per share)	$ 0.01
Preferred stock conversion	$ 400	$ 0	$ 0	$ (411)