Summary of Significant Accounting Policies - Summary of Disaggregation of Revenue (Detail) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2020	Jun. 30, 2019	Jun. 30, 2020	Jun. 30, 2019
Summary Of Significant Accounting Policies [Line Items]
Total	$ 1,134	$ 734	$ 2,717	$ 1,521
Disposables [Member]
Summary Of Significant Accounting Policies [Line Items]
Total	1,122	730	2,179	1,512
Systems [Member]
Summary Of Significant Accounting Policies [Line Items]
Total			520
Product and Service, Other [Member]
Summary Of Significant Accounting Policies [Line Items]
Total	$ 12	$ 4	$ 18	$ 9