XML 51 R45.htm IDEA: XBRL DOCUMENT v2.4.1.9
Property, Plant and Equipment, Net - Additional Information (Detail) (USD $)
12 Months Ended
Dec. 31, 2014
Dec. 31, 2013
Dec. 31, 2012
Property Plant and Equipment Useful Life and Values [Abstract]      
Depreciation expense $ 2,562,000psix_DepreciationExpenses $ 1,528,000psix_DepreciationExpenses $ 1,074,000psix_DepreciationExpenses