Income Taxes - Unrecognized Tax Benefits (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2015	Dec. 31, 2014
Tax credit carryforwards
Interest and penalty expense recognized related to unrecognized tax benefits	$ 200	$ 200	$ 200
Reconciliation of the beginning and ending balance of unrecognized tax benefits
Balance at beginning of year	7,960	7,645
(Decrease) increase in unrecognized tax benefits as a result of tax positions taken during a prior period	(78)	92
Decreases in unrecognized tax benefits related to settlements with tax authorities	(211)
Increases in unrecognized tax benefits as a result of tax positions taken during the current period		223
Balance at end of year	7,671	7,960	7,645
Recorded as other long-term liability				$ 2,142	$ 2,328
Recorded as a decrease in deferred tax assets and offsetting valuation allowance				5,529	5,632
Unrecognized tax benefits	$ 7,960	$ 7,645	$ 7,645	7,671	$ 7,960
Research and development and other tax credit carryforwards
Tax credit carryforwards
Tax credit carryforwards				16,700
Foreign
Tax credit carryforwards
Tax credit carryforwards				$ 3,600