Joint Venture - Summary of Financial Information of Joint Ventures (Balance Sheet Data) (Details) - USD ($) $ in Thousands	Mar. 31, 2022	Dec. 31, 2021	Sep. 30, 2021	Jun. 30, 2021	Mar. 31, 2021	Dec. 31, 2020	Sep. 30, 2020	Jun. 30, 2020
Schedule Of Equity Method Investments [Line Items]
Current assets	$ 347,196			$ 352,773
Total assets	469,436			480,098
LIABILITIES AND STOCKHOLDERS' EQUITY
Current liabilities	201,340			192,359
Stockholder's equity	51,609	$ 50,994	$ 45,765	68,840	$ 78,550	$ 77,778	$ 67,440	$ 63,635
Total liabilities and stockholders' equity	$ 469,436			$ 480,098
CNNC Accuray (Tianjin) Medical Technology Co. Ltd.
Schedule Of Equity Method Investments [Line Items]
Current assets		62,328				19,895
Non current assets		22,136				22,446
Total assets		84,464				42,341
LIABILITIES AND STOCKHOLDERS' EQUITY
Current liabilities		52,085				11,810
Non current liabilities		1,001				1,131
Stockholder's equity		31,378				29,400
Total liabilities and stockholders' equity		$ 84,464				$ 42,341