Fair Value Measurements - Additional Information (Detail) - USD ($)	3 Months Ended		12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Sep. 30, 2017	Sep. 30, 2016
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Transfers in or out Level 3, Assets				$ 0
Transfers in or out Level 3, Liabilities				$ 0
Minimum [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Percentage of Probability Achievement of Contingent Consideration payment.	65.00%
Maximum [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Percentage of Probability Achievement of Contingent Consideration payment.	95.00%
Contingent Consideration [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Foreign currency gain (loss)	$ 700,000	$ (100,000)
Contingent Consideration [Member] | Minimum [Member] | Non Revenue Based Milestones [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Fair Value Inputs, Discount Rate	5.60%
Contingent Consideration [Member] | Minimum [Member] | Revenue Based Milestones [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Fair Value Inputs, Discount Rate	14.10%
Contingent Consideration [Member] | Maximum [Member] | Non Revenue Based Milestones [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Fair Value Inputs, Discount Rate	6.70%
Contingent Consideration [Member] | Maximum [Member] | Revenue Based Milestones [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Fair Value Inputs, Discount Rate	22.80%
Scenario Forecast [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Transfers in or out Level 3, Assets			$ 0
Transfers in or out Level 3, Liabilities			$ 0