Stockholders' Equity - Additional Information (Detail) - USD ($) $ in Thousands						12 Months Ended
	Sep. 23, 2014	Dec. 11, 2013	Oct. 21, 2013	Sep. 06, 2013	May. 08, 2013	Dec. 31, 2013
Schedule Of Capitalization Equity [Line Items]
Warrants exercised to purchase common stock, shares					1,485,010
Proceeds from exercise of common stock warrants					$ 8,000	$ 8,034
Common stock issued for acquisition	2,284,070
Issuance of common stock from public offering, shares			3,910,000
Proceeds from issuance of common stock			$ 174,083			$ 174,083
Paramount Energy Solutions Llc [Member]
Schedule Of Capitalization Equity [Line Items]
Common stock issued for acquisition				3,674,565
Zep Solar [Member]
Schedule Of Capitalization Equity [Line Items]
Common stock issued for acquisition		2,751,782