Summary of Significant Accounting Policies and Select Balance Sheet Information - Additional Information (Detail 1) - Abbott [Member] - R&D and Clinical Activities [Member] - Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date: 2019-01-01 $ in Millions	Sep. 30, 2019 USD ($)
Summary Of Significant Accounting Policies [Line Items]
Estimated revenue to be recognized in future	$ 17.1
Expected period to recognize the remaining revenue	6 years
TRANSCEND Clinical Trial [Member]
Summary Of Significant Accounting Policies [Line Items]
Revenue remaining performance obligation percentage	75.00%
Revenue remaining performance obligation expected timing of satisfaction year	2021
Capitalized contract cost amortization period	4 years
Revenue remaining performance obligation amortization percentage	25.00%