Commitments and Contingencies - Additional Information (Detail) - USD ($)
 12 Months Ended
May 31, 2016
Dec. 31, 2016
Dec. 31, 2015
Dec. 31, 2014
Dec. 31, 2012
Other Commitments [Line Items]          
Deferred lease obligation   $ 1,570,000 $ 585,000    
Lease minimum rental payment   $ 8,815,000      
Stamford Operating Lease [Member]          
Other Commitments [Line Items]          
Operating Lease, description   The Stamford Lease requires monthly lease payments, including rent escalations and rent holidays, during the initial lease term. The Company began to make rental payments from the Commencement Date. The Company records monthly rent expense on a straight-line basis from March 2016, upon taking possession of the Premises, through October 2023. As of December 31, 2016, the balance of deferred lease obligation, representing the difference between cash rent paid and straight-line rent expense, was $583. The Stamford Lease is renewable for one five-year term.      
Operating Lease, renewable term   5 years      
Operating lease, expiration date   Oct. 31, 2023      
Deferred lease obligation   $ 583,000      
Tenant improvement expenses   1,094,000      
Operating lease, rent expense   797,000      
Lease minimum rental payment   8,075,000      
Stamford Operating Lease [Member] | Leasehold Improvements [Member]          
Other Commitments [Line Items]          
Amortization of deferred lease obligation   107,000      
Stamford Operating Lease [Member] | Standby Letter of Credit [Member]          
Other Commitments [Line Items]          
Letter of credit, amount   $ 769,000      
Letter of credit, expiration date   Dec. 16, 2016      
Operating lease, renewable term description   Automatically renewed annually through November 2023.      
Stamford Operating Lease [Member] | Maximum [Member] | Standby Letter of Credit [Member]          
Other Commitments [Line Items]          
Letter of credit, renewal date   Nov. 30, 2023      
Shelton Operating Lease [Member]          
Other Commitments [Line Items]          
Operating lease, expiration date   Oct. 13, 2017      
Operating lease, rent expense   $ 1,127,000 665,000 $ 643,000  
Accrued cease use date liability $ 1,312,000 1,312,000      
Lease minimum rental payment   740,000      
Restructuring liability   756,000      
Accumulated deferred lease obligation, written off $ 429,000        
Incentive allowance received   2,127,000      
Unamortized incentive allowance     374,000    
Accrued rent     211,000    
Additional amortization expense   $ 899,000 $ 67,000    
Additional loss per share   $ 0.03      
Shelton Operating Lease [Member] | Standby Letter of Credit [Member]          
Other Commitments [Line Items]          
Letter of credit, amount   $ 2,170,000      
Letter of credit, expiration date   May 31, 2017      
Amounts of drawings against letter of credit   $ 0      
Letter of credit, annual reduction from 2008 to 2012         $ 294,000
Letter of credit, remaining amount         $ 700,000