Commitments and Contingencies - Additional Information (Detail) (USD $) In Millions, unless otherwise specified	3 Months Ended	9 Months Ended
	Sep. 30, 2014	Sep. 30, 2014	Dec. 31, 2013	Sep. 30, 2013
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		8.0
Incentive awarded to the company by the State of Connecticut, grants		3.5
Non-interest bearing incentive loan term		10 years
Incentive awarded to the company by the State of Connecticut, deferred revenue	6.4	6.4	7.2	7.5
Incentive awarded to the company by the State of Connecticut, revenue recognized	$ 0.3	$ 0.8