Segment Reporting - Revenue by Geographic Area (Detail) (USD $) In Thousands, unless otherwise specified	3 Months Ended								12 Months Ended
	Dec. 31, 2014	Sep. 30, 2014	Jun. 30, 2014	Mar. 31, 2014	Dec. 31, 2013	Sep. 30, 2013	Jun. 30, 2013	Mar. 31, 2013	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Revenue by geographic area
Total revenue	$ 19,551	$ 132,871	$ 28,513	$ 19,771	$ 31,146	$ 60,909	$ 33,862	$ 23,004	$ 200,707	$ 148,921	$ 81,191
Reportable Geographical Components [Member] | United States [Member]
Revenue by geographic area
Total revenue									32,514	42,535	34,591
Reportable Geographical Components [Member] | European [Member]
Revenue by geographic area
Total revenue									$ 168,193	$ 106,386	$ 46,600