Summary of Significant Accounting Policies - Additional Information (Details) - USD ($) $ in Thousands	3 Months Ended	36 Months Ended
	Mar. 31, 2017	Dec. 31, 2016	Oct. 24, 2014
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale securities	$ 1,310	$ 1,106
Nicox
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale securities	1,300
Unrealized gain (loss) on securities	1,700
Original cost basis			$ 10,800
Original cost of investments sold		$ 9,200
Proceeds from sale of investment	6,000
Unrealized gain (loss) on investment	(200)
Initial Value | Nicox
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale securities	$ 12,500
Minimum
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Intangible asset useful life (in years)	1 year
Maximum
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Intangible asset useful life (in years)	30 years