Note 4. Restructuring and Acquisitions (Details) - Acquisitions (USD $)			0 Months Ended		6 Months Ended	12 Months Ended		0 Months Ended	12 Months Ended
	Dec. 31, 2011	Dec. 31, 2010	Jan. 04, 2011 Ray Tracker [Member]	Jul. 12, 2010 NextLight [Member]	Jul. 12, 2010 NextLight [Member]	Dec. 31, 2010 NextLight [Member]	Dec. 31, 2009 NextLight [Member]	Apr. 03, 2009 Project Development Business of OptiSolar [Member]	Dec. 31, 2011 Project Development Business of OptiSolar [Member]	Dec. 26, 2009 Project Development Business of OptiSolar [Member]	Apr. 16, 2010 Project Development Business of OptiSolar [Member]
Business Acquisition [Line Items]
Business acquisition, effective date of acquisition			1/4/2011	7/12/2010				4/3/2009
Business Acquisition, Purchase Price Allocation [Abstract]
Outstanding membership interests acquired (percentage)			100.00%
Business Acquisition, Total Purchase Consideration				$ 296,740,000	$ 296,740,000			$ 399,434,000
Business Acquisition, Purchase Price Allocation, Net Tangible Assets				2,513,000	2,513,000			10,175,000
Business Acquisition, Purchase Price Allocation, Project Assets	5,731,000	217,417,000		147,370,000	147,370,000			103,888,000
Business Acquisition, Purchase Price Allocation, Deferred Tax Assets				84,000	84,000			35,195,000
Business Acquisition, Purchase Price Allocation, Goodwill				146,773,000	146,773,000			250,176,000
Business Acquisition, Purchase Price Allocation, Current Assets, Cash and Cash Equivalents				244,000	244,000			318,000
Business Acquisition, Purchase Price Allocation, Current Assets, Prepaid Expense and Other Assets				346,000	346,000			5,003,000
Business Acquisition, Purchase Price Allocation, Property, Plant and Equipment				996,000	996,000			165,000
Business Acquisition, Purchase Price Allocation, Land				3,380,000	3,380,000			6,100,000
Business Acquisition, Purchase Price Allocation, Assets Acquired				4,966,000	4,966,000			11,586,000
Business Acquisition, Purchase Price Allocation, Current Liabilities				(2,453,000)	(2,453,000)			(1,411,000)
Business Acquisition, Purchase Price Allocation, Liabilities Assumed, Total				(2,453,000)	(2,453,000)			(1,411,000)
Business Acquisition, Cost of Acquired Entity [Abstract]
Business Acquisition, Merger Shares Issued or Issuable								2,972,420
Business Acquisition, Acquiree Pro Forma Net Loss					9,100,000		13,400,000
Business Acquisition, Shares Issued And Placed Into Escrow								732,789
Common Stock, Par Value	$ 0.001	$ 0.001
Business Acquisition, Shares Issued And Released From Escrow											146,558
Business Acquisition, Holdback Shares Issuable, Value Assigned								355,096
Sale of Stock, Price Per Share								$ 134.38
Business Acquisition Holdback Shares Issued									8,316
Business Acquisition Cost Of Acquired Entity Integration Costs										600,000
Business Combination, Acquisition Related Costs						$ 1,900,000				$ 1,600,000