Assets Held for Sale - Additional Information (Detail) (USD $)	1 Months Ended		3 Months Ended	9 Months Ended	12 Months Ended
	Jun. 30, 2012	May 31, 2012	Sep. 30, 2011	Sep. 30, 2012	Dec. 31, 2010	Dec. 31, 2009	Dec. 31, 2011
Related Party Transaction [Line Items]
Asset held for sale				$ 0	$ 10,000,000		$ 11,777,000	[1]
Asset held for sale reduced					6,700,000	3,300,000
Maximum period of sale for asset held for sale					21 months
Impairment charge		700,000	400,000
Amount assigned from asset sale to loan obligation	4,200,000			4,200,000
Net proceeds from sale of assets held for sale	1,500,000			1,500,000
SGT [Member]
Related Party Transaction [Line Items]
Asset held for sale							$ 5,500,000

[1] As recast to reflect the balances of Solar Green Technology S.p.A. ("SGT") beginning January 1, 2011 combined with the balances of Solar Power, Inc. beginning March 31, 2011, as required under the accounting guidelines for a transfer of an entity under common control (refer to Note 4-Acquisition of Solar Green Technology).