Accrued Liabilities (Details) (USD $) In Thousands, unless otherwise specified	Mar. 31, 2013	Dec. 31, 2012		Mar. 31, 2012	Dec. 31, 2011
Components of accrued liabilities [Abstract]
Dividends payable by consolidated joint ventures	$ 2,365	$ 0		$ 655
Accrued compensation and related charges	1,424	2,066
Current portion of royalty payments	800	800
Accrued income taxes	521	640
Accrued professional services	312	609
Accrued product warranty	749	588		997	1,003
Other accrued liabilities	3,263	2,499
Accrued liabilities, total	$ 9,434	$ 7,202	[1]

[1] The condensed consolidated balance sheet at December 31, 2012 has been derived from the audited consolidated financial statements at that date.