Commitments and Contingencies - Additional Information (Detail) - USD ($)
 12 Months Ended
Oct. 31, 2015
Mar. 30, 2015
Dec. 31, 2015
Dec. 31, 2014
Dec. 31, 2013
Commitments And Contingencies [Line Items]          
Operating lease rent expense     $ 3,766,000 $ 3,667,000 $ 3,558,000
Sub-lease income     433,000 379,000 805,000
Assets acquired under capital leases     50,000 321,000  
Depreciation expense     719,000 546,000 423,000
Contingent consideration payments       1,805,000 703,000
Payments recorded as compensation expense     3,000 0  
Capital Lease Assets          
Commitments And Contingencies [Line Items]          
Depreciation expense     $ 123,000 81,000 19,000
Jamison          
Commitments And Contingencies [Line Items]          
Contingent consideration payments   $ 3,550,000      
MCG Acquisition | Contingent Consideration          
Commitments And Contingencies [Line Items]          
Contingent consideration percentage of EBITDA     22.00%    
Number of years contingent consideration adjusted annual EBITDA     5 years    
Contingent consideration payments     $ 0 1,805,000 703,000
Additional Office Space          
Commitments And Contingencies [Line Items]          
Operating lease rent expense, net     5,000    
Refundable security deposit     $ 3,000    
Lease commencement date     May 01, 2014    
Lease expires     Jul. 31, 2019    
Number of rent free periods     3 months    
Office Space | Charlottesville, VA.          
Commitments And Contingencies [Line Items]          
Operating lease rent expense, net     $ 2,000    
Refundable security deposit     $ 2,000    
Lease commencement date     Jun. 30, 2015    
Lease expires     Jun. 30, 2018    
Number of rent free periods     2 months    
Office Space | Bedminster, NJ.          
Commitments And Contingencies [Line Items]          
Operating lease rent expense, net     $ 11,000    
Lease expires     Mar. 31, 2022    
Number of rent free periods     4 months    
Office Space | Princeton, NJ.          
Commitments And Contingencies [Line Items]          
Operating lease rent expense, net     $ 6,000    
Lease expires     Aug. 31, 2022    
Office Space | New York City          
Commitments And Contingencies [Line Items]          
Operating lease rent expense, net     $ 446,000    
Lease commencement date     Oct. 01, 2017    
Lease expires     Sep. 30, 2028    
Number of rent free periods     12 months    
Payments for tenant improvements     $ 2,080,000    
Office Equipment          
Commitments And Contingencies [Line Items]          
Capital lease obligation     $ 440,000 282,000  
Office Equipment | Telephone System          
Commitments And Contingencies [Line Items]          
Lease expires     Nov. 30, 2018    
Assets acquired under capital leases     $ 321,000    
Capital lease, period     5 years    
Capital lease, minimum monthly payment     $ 5,000    
Office Equipment | Copier          
Commitments And Contingencies [Line Items]          
Lease expires Oct. 31, 2018   Jun. 30, 2018    
Assets acquired under capital leases $ 18,000   $ 21,000    
Capital lease, period 3 years   3 years    
Capital lease, minimum monthly payment $ 1,000   $ 1,000    
Office Equipment | Jamison          
Commitments And Contingencies [Line Items]          
Assets acquired under capital leases     253,000    
Letter of Credit          
Commitments And Contingencies [Line Items]          
Refundable security deposit     587,000 587,000  
Letter of Credit | Boston landlord          
Commitments And Contingencies [Line Items]          
Refundable security deposit     80,000    
General and administrative          
Commitments And Contingencies [Line Items]          
Operating lease rent expense, net     $ 3,333,000 $ 3,288,000 $ 2,753,000