Quarterly report pursuant to Section 13 or 15(d)

Long-Term Debt - Novartis Note - Additional Information (Details)

v3.7.0.1
Long-Term Debt - Novartis Note - Additional Information (Details) - USD ($)
1 Months Ended 6 Months Ended
May 31, 2005
Jun. 30, 2017
Dec. 31, 2016
Novartis Note [Member]      
Debt Instrument [Line Items]      
Maturity date Jun. 30, 2015    
Research and development expenses funded through loan facility, maximum 75.00%    
Maximum borrowing capacity under loan agreement $ 50,000,000    
Interest rate at period end   3.44%  
Outstanding principal balance   $ 14,300,000 $ 14,100,000
Novartis Note [Member] | Six-month LIBOR [Member]      
Debt Instrument [Line Items]      
Basis spread on variable rate   2.00%  
Secured Note Amendment [Member]      
Debt Instrument [Line Items]      
Maturity date   Sep. 30, 2020  
Reduction in outstanding principal amount   $ 7,300,000