Commitments, Contingencies & Guarantees - Additional Information (Detail) - USD ($) $ in Millions	1 Months Ended	3 Months Ended	6 Months Ended
	Sep. 30, 2013	Jun. 30, 2015	Jun. 30, 2015	Dec. 31, 2014
Loss Contingencies [Line Items]
Incentive awarded to the company by the State of Connecticut, total			$ 11.5
Incentive awarded to the company by the State of Connecticut, non-interest bearing loans	$ 6.0		8.0
Incentive awarded to the company by the State of Connecticut, grants	1.5		$ 3.5
Non-interest bearing incentive loan term			10 years
Incentive awarded to the company by the State of Connecticut, revenue recognized		$ 0.3	$ 0.5
Incentive awarded to the company by the State of Connecticut, deferred revenue	$ 7.5	$ 5.6	$ 5.6	$ 6.1