Fair Value Measurements and Fair Value of Financial Instruments - Quantitative Information About Inputs and Valuation Methodologies Used for Fair Value Measurements (Detail) - Financing Arrangement [Member] $ in Thousands	12 Months Ended
	Dec. 31, 2016 USD ($)
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Other noncurrent liability	$ 74
Significant Unobservable Inputs (Level 3) [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Other noncurrent liability	$ 74
Valuation Methodology	Expected value approach
Discount rate	5.50%
Significant Unobservable Inputs (Level 3) [Member] | Minimum [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Milestone dates	2017
Percent probability of milestone achievements	18.20%
Significant Unobservable Inputs (Level 3) [Member] | Maximum [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Milestone dates	2023
Percent probability of milestone achievements	80.00%