Summary of Significant Accounting Policies - Fair Value of Financial Instruments (Details) - USD ($) $ in Thousands	1 Months Ended	9 Months Ended	12 Months Ended	36 Months Ended
	Jun. 30, 2017	Sep. 30, 2017	Dec. 31, 2014	Dec. 31, 2016	May 31, 2017
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value of available-for-sale securities		$ 33		$ 1,106
Nicox
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value of available-for-sale securities					$ 3,000
Original cost basis			$ 10,800
Unrealized gain (loss) on securities			1,700
Original cost of investments sold		1,500		$ 9,200
Gain realized on sale of securities		$ 200
Proceeds from sale of investment	$ 2,600
Loss on sale of securities, net	$ 400
Initial Value | Nicox
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value of available-for-sale securities			$ 12,500
Minimum
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Intangible asset useful life		1 year
Maximum
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Intangible asset useful life		30 years