Note 7 - Note Receivable (Detail) (USD $)	Dec. 31, 2012	Dec. 31, 2011		Mar. 31, 2013 Subsequent Event [Member] Solar Hub [Member]	Dec. 31, 2012 EPC Contract [Member]	Dec. 31, 2011 EPC Contract [Member]	Jun. 08, 2012 Solar Hub [Member] Maximum [Member]	Dec. 31, 2012 Solar Hub [Member]	Jun. 08, 2012 Solar Hub [Member]	Apr. 27, 2012 Solar Hub [Member]
Note Receivable, Interest Rate				10.00%	5.00%				6.00%
Financing Receivable, Net	$ 14,120,000	$ 5,862,000	[1]		$ 7,000,000	$ 5,900,000		$ 7,100,000
Financing Receivable, Gross							$ 9,000,000			$ 1,000,000

[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 5 -Acquisition of Solar Green Technology).