Stockholders' Equity (Deficit) - Common and Treasury Stock and Series B Convertible Preferred Stock (Details)	12 Months Ended
	Dec. 31, 2021 stockSeries $ / shares shares	Dec. 31, 2020 $ / shares shares
Common Shares Issued
Beginning balance (in shares)	23,117,000	23,117,000
Ending balance (in shares)	23,117,000	23,117,000
Treasury Stock Shares
Beginning balance (in shares)	225,000	260,000
Net shares issued for stock awards (in shares)	(34,000)	(35,000)
Ending balance (in shares)	191,000	225,000
Common Shares Outstanding
Beginning balance (in shares)	22,892,000	22,857,000
Ending balance (in shares)	22,926,000	22,892,000
Series B convertible preferred stock, authorized (in shares)	5,000,000	5,000,000
Series B convertible preferred stock, par value (in dollars per share) | $ / shares	$ 0.001	$ 0.001
Preferred stock, shares outstanding (in shares)	0	0
Common Stock
Common Shares Outstanding
Net shares issued for stock awards (in shares)	34,000	35,000
Series B Convertible Preferred Stock
Common Shares Outstanding
Series B convertible preferred stock, authorized (in shares)	5,000,000
Series B convertible preferred stock, par value (in dollars per share) | $ / shares	$ 0.001
Number of authorized series of preferred stock | stockSeries	2