Quarterly report pursuant to Section 13 or 15(d)

Fair Value - Narrative (Details)

v3.7.0.1
Fair Value - Narrative (Details) - USD ($)
Mar. 31, 2017
Dec. 31, 2016
Money market funds | Fair value measured on a recurring basis    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Fair value $ 17,300,000 $ 55,800,000
Level 3    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Total assets measured at fair value 0 0
Liabilities measured at fair value $ 0 $ 0