Marketable Equity Investments - Additional Information (Detail) - USD ($)	1 Months Ended	12 Months Ended
	Apr. 30, 2015	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Investment [Line Items]
Eligibility to receive a royalty fee		1.00%
Royalty income, nonoperating		$ 0	$ 0	$ 0
Carrying value of investment		0
Gain on sale of investment in marketable equity securities		$ 750,000
Common stock, shares outstanding		99,095,000	99,095,000
Aduro
Investment [Line Items]
Preferred shares converted to common stock	396,700
Sale of common stock in marketable equity investment		50,000
Gain on sale of investment in marketable equity securities		$ 800,000
Common stock, shares outstanding		346,700