Revenue - Additional Information (Detail) - USD ($)	3 Months Ended	12 Months Ended
	Dec. 31, 2018	Sep. 30, 2018
Abbott [Member]
Disaggregation Of Revenue [Line Items]
Upfront fee received	$ 25,000,000	$ 25,000,000
Abbott [Member] | SurVeil DCB [Member]
Disaggregation Of Revenue [Line Items]
Clinical study completion period	6 years
Minimum [Member]
Disaggregation Of Revenue [Line Items]
Product sales payment terms	30 days
Payment period set for R&D services	30 days
Maximum [Member]
Disaggregation Of Revenue [Line Items]
Product sales payment terms	45 days
Sales-based and minimum royalties due period	45 days
Payment period set for R&D services	45 days
Maximum [Member] | Abbott [Member]
Disaggregation Of Revenue [Line Items]
Collaborative arrangement additional potential milestone payments receivable	$ 67,000,000