Schedule II - Valuation and Qualifying Accounts (Details) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2012		Dec. 31, 2011		Dec. 31, 2010
Allowance for Doubtful Accounts and Sales Returns [Member]
Movement in Valuation Allowances and Reserves [Roll Forward]
Balance at Beginning of Year	$ 602		$ 790		$ 948
Additions Charged (Credited) to Revenue, Costs or Expenses	959		765		921
Deductions	972	[1]	953	[1]	1,079	[1]
Balance at End of Year	589		602		790
Inventory Valuation Reserve [Member]
Movement in Valuation Allowances and Reserves [Roll Forward]
Balance at Beginning of Year	925		779		380
Additions Charged (Credited) to Revenue, Costs or Expenses	156		534		418
Deductions	167	[1]	388	[1]	19	[1]
Balance at End of Year	914		925		779
Valuation Allowance of Deferred Tax Assets [Member]
Movement in Valuation Allowances and Reserves [Roll Forward]
Balance at Beginning of Year	14,022		18,412		12,735
Additions Charged (Credited) to Revenue, Costs or Expenses	(1,241)		(1,973)		8,571
Deductions	0	[1]	2,417	[1]	2,894	[1]
Balance at End of Year	$ 12,781		$ 14,022		$ 18,412

[1] Deductions represent receivables written-off and credits granted for customer returns, inventory write-offs, and reductions in the valuation allowance for deferred tax assets due primarily to the use or expiration of net operating losses.