Fair Value Measurement (Details) (USD $)
3 Months Ended
Mar. 31, 2015
Mar. 31, 2014
Dec. 31, 2014
Reconciliation of the beginning and ending balances of the liabilities measured at fair value      
Increase related to acquisition of OFS $ (1,500,000)    
Contingent consideration      
Liabilities:      
Contingent consideration obligation (4,069,311)    
Minimum      
Fair value measurement:      
Discount rate used to determine fair value of contingent consideration 2.00%    
Maximum      
Fair value measurement:      
Discount rate used to determine fair value of contingent consideration 18.00%    
Level 3      
Reconciliation of the beginning and ending balances of the liabilities measured at fair value      
Balance at beginning of period (5,331,078)    
Change in fair value 95,934    
Settlements 2,665,833    
Balance at end of period (4,069,311)    
Level 3 | Contingent consideration      
Reconciliation of the beginning and ending balances of the liabilities measured at fair value      
Settlements   1,244,670  
Level 3 | Selling, general and administrative expenses      
Reconciliation of the beginning and ending balances of the liabilities measured at fair value      
Change in fair value 95,934 (224,162)  
Fair Value, Measurements, Recurring | Contingent consideration      
Liabilities:      
Contingent consideration obligation (4,069,311)   (5,331,078)
Fair Value, Measurements, Recurring | Level 1 | Contingent consideration      
Liabilities:      
Contingent consideration obligation 0   0
Fair Value, Measurements, Recurring | Level 2 | Contingent consideration      
Liabilities:      
Contingent consideration obligation 0   0
Fair Value, Measurements, Recurring | Level 3 | Contingent consideration      
Liabilities:      
Contingent consideration obligation $ (4,069,311)   $ (5,331,078)