Accrued Liabilities (Details) - USD ($) $ in Thousands	Sep. 30, 2016	Dec. 31, 2015	Sep. 30, 2015
Components of accrued liabilities [Abstract]
Accrued compensation and related charges	$ 1,161	$ 2,129
Current portion of royalty payments	575	575
Dividends payable by consolidated joint ventures	520	534	$ 544
Accrued professional services	531	709
Accrued product warranty	266	497
Accrued income taxes	249	225
Other accrued liabilities	1,709	1,712
Accrued liabilities, total	$ 5,011	$ 6,381