Income Taxes (Details 4) (USD $)	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013
Deferred tax assets:
Inventory valuation	$ 8,244,000	$ 6,983,000
Net operating losses and credit carry forwards	39,750,000	18,972,000
Warranty and installation accruals	2,452,000	3,002,000
Share-based compensation	11,794,000	10,638,000
Other	2,647,000	3,716,000
Total deferred tax assets	64,887,000	43,311,000
Valuation allowance	(34,909,000)	(7,753,000)
Net deferred tax assets	29,978,000	35,558,000
Deferred tax liabilities:
Purchased intangible assets	34,018,000	45,208,000
Undistributed earnings	1,047,000	1,737,000
Depreciation	2,274,000	4,711,000
Total deferred tax liabilities	37,339,000	51,656,000
Net deferred taxes	(7,361,000)	(16,098,000)
Undistributed earnings of foreign subsidiaries	115,800,000	101,000,000
Valuation allowance
Increase in valuation allowance	27,200,000
Federal
Valuation allowance
Net operating loss carryforwards	53,300,000
Research and development tax credits	9,200,000
Foreign
Valuation allowance
Net tax credit carryforwards	$ 7,000,000