Information about Geographic Areas (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended								12 Months Ended
	Dec. 31, 2012	Sep. 30, 2012	Jun. 30, 2012	Mar. 31, 2012	Dec. 31, 2011	Sep. 30, 2011	Jun. 30, 2011	Mar. 31, 2011	Dec. 31, 2012	Dec. 31, 2011
Total revenue:
Total revenue	$ 25,856	$ 25,485	$ 24,505	$ 25,548	$ 23,384	$ 24,029	$ 23,422	$ 26,008	$ 101,394	$ 96,843
Long-lived assets:
Total long-lived assets	8,813				9,464				8,813	9,464
North America [Member]
Total revenue:
Total revenue									71,936	74,699
Long-lived assets:
Total long-lived assets	3,663				4,334				3,663	4,334
Asia [Member]
Total revenue:
Total revenue									23,721	17,909
Long-lived assets:
Total long-lived assets	447				111				447	111
Europe [Member]
Total revenue:
Total revenue									5,694	4,151
Long-lived assets:
Total long-lived assets	4,703				5,019				4,703	5,019
Other foreign [Member]
Total revenue:
Total revenue									$ 43	$ 84