Income Taxes (Details) (USD $)	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Income (loss) before income taxes
United States	$ (37,682,000)	$ 2,622,000	$ (21,526,000)
Foreign	5,294,000	4,849,000	4,265,000
Income (loss) before income taxes	(32,388,000)	7,471,000	(17,261,000)
Current:
United States, State	82,000	163,000	309,000
Foreign	738,000	1,646,000	1,528,000
Total current	820,000	1,809,000	1,837,000
Deferred:
Foreign	826,000	585,000	(1,525,000)
Total deferred	826,000	585,000	(1,525,000)
Income taxes	1,646,000	2,394,000	312,000
Reconciliations of income taxes at the United States Federal statutory rate to the effective income tax rate
Income (credit) at the United States statutory rate	(11,336,000)	2,615,000	(6,041,000)
State income taxes	53,000	31,000	309,000
Unrecognized tax benefits	(832,000)	899,000	842,000
Effect of change in valuation allowance	12,662,000	(3,160,000)	6,550,000
Foreign income tax rate differentials	(788,000)	(365,000)	(1,490,000)
Restoration of foreign deferred tax assets			(1,329,000)
Foreign dividend	383,000
Stock options	1,298,000
Deemed distribution from foreign subsidiaries	149,000	1,533,000	2,152,000
Other, net	57,000	841,000	(681,000)
Income taxes	1,646,000	2,394,000	312,000
Significant components of current deferred income taxes
Accrued compensation	352,000	541,000
Inventories	22,582,000	22,447,000
Warranty	612,000	1,293,000
Other	1,820,000	1,243,000
Deferred taxes, gross	25,366,000	25,524,000
Valuation allowance	(25,062,000)	(24,160,000)
Deferred taxes, net	304,000	1,364,000
Significant components of long-term deferred income taxes
Federal net operating loss carryforwards	88,088,000	79,163,000
State net operating loss carryforwards	1,181,000	2,685,000
Foreign net operating loss carryforwards	1,853,000	1,821,000
Unremitted earnings of foreign subsidiaries	(8,580,000)	(10,370,000)
Intangible assets	661,000	803,000
Property, plant and equipment	5,925,000	5,589,000
Accrued compensation	368,000
Inventories	(215,000)
Stock compensation	4,378,000	3,970,000
Warranty	36,000	51,000
Other	917,000	(3,814,000)
Deferred taxes, gross	121,477,000	104,454,000
Valuation allowance	(119,605,000)	(102,814,000)
Deferred taxes, net	1,872,000	1,640,000
Deferred tax assets	146,800,000
Federal
Tax credit carryforwards
Tax credit carryforwards	17,814,000	15,505,000
State
Tax credit carryforwards
Tax credit carryforwards	$ 9,051,000	$ 9,051,000