Prepaid Expenses and Other Current Assets - Additional Information (Detail)	Mar. 31, 2015 USD ($)	Dec. 31, 2014 USD ($)	Mar. 31, 2015 Solar Panels [Member] USD ($)	Dec. 31, 2014 Solar Panels [Member] USD ($)	Mar. 31, 2015 Prepaid Expenses and Other Current Assets [Member] State Grid Corporation Of China [Member] USD ($)	Mar. 31, 2015 Prepaid Expenses and Other Current Assets [Member] State Grid Corporation Of China [Member] CNY	Dec. 31, 2014 Prepaid Expenses and Other Current Assets [Member] State Grid Corporation Of China [Member] USD ($)	Dec. 31, 2014 Prepaid Expenses and Other Current Assets [Member] State Grid Corporation Of China [Member] CNY
Schedule of Prepaid Expenses and Other Current Assets (Details) [Line Items]
Prepaid expenses and other current assets	$ 38,527,000	$ 10,930,000	$ 5,239,000	$ 0
Value-added tax recoverable			8,156,000	3,969,000
Deposit Assets					$ 4,839,000	30,000,000	$ 4,827,000	30,000,000