Revenue - Schedule of Net Revenue by Organ and Country (Detail) - USD ($) $ in Thousands		12 Months Ended
		Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Disaggregation Of Revenue [Line Items]
Total revenue		$ 93,459	$ 30,262	$ 25,639
United States [Member]
Disaggregation Of Revenue [Line Items]
Total revenue	[1]	84,038	21,861	19,239
All Other Countries [Member]
Disaggregation Of Revenue [Line Items]
Total revenue		9,421	8,401	6,400
Lung revenue [Member] | United States [Member]
Disaggregation Of Revenue [Line Items]
Total revenue	[1]	7,967	9,843	5,392
Lung revenue [Member] | All Other Countries [Member]
Disaggregation Of Revenue [Line Items]
Total revenue		880	822	802
Heart revenue [Member] | United States [Member]
Disaggregation Of Revenue [Line Items]
Total revenue	[1]	29,902	10,103	8,599
Heart revenue [Member] | All Other Countries [Member]
Disaggregation Of Revenue [Line Items]
Total revenue		8,451	7,579	5,598
Liver revenue [Member] | United States [Member]
Disaggregation Of Revenue [Line Items]
Total revenue	[1]	46,169	$ 1,915	$ 5,248
Liver revenue [Member] | All Other Countries [Member]
Disaggregation Of Revenue [Line Items]
Total revenue		$ 90

[1] Revenue by country is categorized based on the location of the end customer. Total revenue includes product and service revenue. Net revenue includes product revenue only.