Income Taxes - Deferred Tax Assets and Liabilities (Details) (USD $)	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011
Operating Loss Carryforwards [Line Items]
Valuation allowance	$ 59,740,000	$ 67,773,000
Decreased in valuation allowance	(8,000,000)
Operating loss carryforwards, federal	157,100,000
Operating loss carryforwards, state	82,000,000
Tax credit carryforwards research and development and other, federal	4,700,000
Tax credit carryforwards research and development and other, state	5,400,000
Excess tax benefits from employee stock purchase plan	3,500,000	3,300,000
Decrease in foreign tax	634,000
Benefit of the tax holiday on net income per share (diluted)	$ 0.02
Unremitted earnings from foreign subsidiaries	5,000,000
WithholdingTaxesPayableUponRemittanceOfPreviouslyUnremittedEarnings	2,000,000
Deferred tax assets:
Tax loss carryforwards	55,288,000	59,457,000
Tax credit carryforwards	19,000	18,000
Uniform capitalization, contract and inventory related reserves	895,000	1,319,000
Accrued vacation	642,000	631,000
Stock-based compensation	813,000	763,000
Tax basis depreciation less book depreciation	0	984,000
Intangible assets	1,104,000	1,232,000
Deferred revenue	152,000	265,000
FCPA settlement	0	1,187,000
Other	1,185,000	1,849,000
Deferred Tax Assets, Gross	60,098,000	67,705,000
Deferred tax liabilities:
Inventory deduction	(209,000)	(185,000)
Pension assets	(1,385,000)	(933,000)
Allowance for doubtful accounts	(433,000)	(245,000)
Tax basis depreciation less book depreciation	(224,000)	0
Other	0	(1,000)
Deferred Tax Liabilities, Gross	2,251,000	1,364,000
Net deferred tax assets before valuation allowance	57,847,000	66,341,000
Valuation allowance	(59,740,000)	(67,773,000)
Net deferred tax liabilities	(1,893,000)	(1,432,000)
Deferred tax asset stock option deductions [Member]
Operating Loss Carryforwards [Line Items]
Valuation allowance	(15,500,000)
Deferred tax liabilities:
Valuation allowance	$ 15,500,000