Income Taxes (Details) (USD $)	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Income (loss) before income taxes
United States	$ (18,998,000)	$ (37,682,000)	$ 2,622,000
Foreign	2,894,000	5,294,000	4,849,000
Income (loss) before income taxes	(16,104,000)	(32,388,000)	7,471,000
Current:
United States, State	84,000	82,000	163,000
Foreign	641,000	738,000	1,646,000
Total current	725,000	820,000	1,809,000
Deferred:
Foreign	315,000	826,000	585,000
Total deferred	315,000	826,000	585,000
Income taxes	1,040,000	1,646,000	2,394,000
Reconciliations of income taxes at the United States Federal statutory rate to the effective income tax rate
Income tax (benefits) at the United States statutory rate	(5,636,000)	(11,336,000)	2,615,000
State income taxes	55,000	53,000	31,000
Unrecognized tax benefits	(293,000)	(832,000)	899,000
Effect of change in valuation allowance	5,975,000	12,662,000	(3,160,000)
Foreign income tax rate differentials	(1,244,000)	(788,000)	(365,000)
Restoration of foreign deferred tax assets	961,000
Foreign dividend		383,000
Stock options	450,000	1,298,000
Deemed distribution from foreign subsidiaries	316,000	149,000	1,533,000
Other, net	456,000	57,000	841,000
Income taxes	1,040,000	1,646,000	2,394,000
Significant components of current deferred income taxes
Accrued compensation	43,000	352,000
Inventories	16,540,000	22,582,000
Warranty	591,000	612,000
Other	2,671,000	1,820,000
Deferred taxes, gross	19,845,000	25,366,000
Valuation allowance	(18,059,000)	(25,062,000)
Deferred taxes, net	1,786,000	304,000
Significant components of long-term deferred income taxes
Federal net operating loss carryforwards	104,370,000	88,088,000
State net operating loss carryforwards	2,250,000	1,181,000
Foreign net operating loss carryforwards	1,421,000	1,853,000
Unremitted earnings of foreign subsidiaries	(9,661,000)	(8,580,000)
Intangible assets	532,000	661,000
Property, plant and equipment	4,796,000	5,925,000
Accrued compensation		368,000
Inventories		(215,000)
Stock compensation	4,896,000	4,378,000
Warranty	(56,000)	36,000
Other	(2,406,000)	917,000
Deferred taxes, gross	129,499,000	121,477,000
Valuation allowance	(129,409,000)	(119,605,000)
Deferred taxes, net	90,000	1,872,000
Deferred tax assets	149,300,000
Federal
Tax credit carryforwards
Tax credit carryforwards	17,814,000	17,814,000
State
Tax credit carryforwards
Tax credit carryforwards	$ 5,543,000	$ 9,051,000