Income Taxes (Details) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Current:
Federal	$ (3,994)	$ 2,697
State	289	326	231
Current income tax expense (benefit)	(3,705)	3,023	231
Deferred:
Federal	7,375	7,855	363
State	474	454	278
Deferred income tax expense (benefit)	7,849	8,309	641
Provision for income tax expense (benefit)	4,144	11,332	872
Reconciliation of income tax expense computed at the federal statutory rate to the provision for income taxes
Federal income tax expense at statutory rate	3,555	10,630	862
State taxes, net of federal benefit	218	1,522	7
Valuation allowance changes	451	(47)	311
Change in uncertain tax positions, net	8	(150)	(349)
Research and development credit	(26)	(111)	(117)
Rate change	67	(162)	95
Manufacturing tax benefits		(552)
Other	(129)	202	63
Provision for income tax expense (benefit)	$ 4,144	$ 11,332	$ 872