Income Taxes (Details 2) (USD $)	Dec. 31, 2011	Dec. 31, 2010
Income Taxes [Line Items]
Valuation allowance	$ (6,700,000)
Deferred income taxes, net	27,443,000	23,128,000
Deferred income taxes, net	31,644,000	22,742,000
Deferred income taxes	(17,237,000)	(13,163,000)
Net deferred tax assets	41,800,000
Cumulative amount of earnings upon which United States income taxes have not been provided	552,000,000
Domestic
Income Taxes [Line Items]
Operating loss carry-forwards	77,700,000
State taxes
Income Taxes [Line Items]
Operating loss carry-forwards	67,500,000
Current deferred tax assets
Income Taxes [Line Items]
Deferred income taxes, net	27,443,000	23,128,000
Current deferred tax assets | Domestic
Income Taxes [Line Items]
Allowance for doubtful accounts	595,000	800,000
Accrued product warranties	2,964,000	2,862,000
Inventory	10,295,000	7,957,000
Accrued liabilities	9,499,000	10,121,000
Deferred revenue	2,568,000	1,256,000
Net operating loss carry-forwards	844,000	376,000
Other	(1,602,000)	(746,000)
Current deferred tax assets | Foreign
Income Taxes [Line Items]
Inventory	0	893,000
Accrued liabilities	1,402,000	568,000
Intangibles	(255,000)	(1,312,000)
Other	1,133,000	353,000
Noncurrent deferred tax assets | Domestic
Income Taxes [Line Items]
Deferred revenue	5,599,000	3,704,000
Net operating loss carry-forwards	28,826,000	39,531,000
Credit carry-forwards	6,175,000	2,477,000
Domestic depreciation	(8,682,000)	(11,796,000)
Supplemental Executive Retirement Plan	7,684,000	6,415,000
Stock-based compensation	11,978,000	10,690,000
Intangibles	(22,436,000)	(26,888,000)
Other	7,561,000	4,172,000
Valuation allowance	(5,061,000)	(5,563,000)
Deferred income taxes, net	31,644,000	22,742,000
Noncurrent deferred tax liabilities
Income Taxes [Line Items]
Deferred income taxes	(17,237,000)	(13,163,000)
Noncurrent deferred tax liabilities | Domestic
Income Taxes [Line Items]
Valuation allowance	(1,659,000)	(1,746,000)
Noncurrent deferred tax liabilities | Foreign
Income Taxes [Line Items]
Foreign net operating loss recapture	(550,000)	(531,000)
Foreign credit carry-forwards	632,000	166,000
Foreign depreciation	3,431,000	3,426,000
Foreign stock-based compensation	788,000	1,080,000
Foreign social costs	(462,000)	(860,000)
Foreign intangibles	(23,074,000)	(17,543,000)
Foreign pension	33,000	26,000
Foreign net operating loss carry-forwards	2,877,000	2,438,000
Foreign other	$ 747,000	$ 381,000