Joint Venture - Summary of Financial Information of Joint Ventures (Balance Sheet Data) (Details) - USD ($) $ in Thousands	Dec. 31, 2021	Sep. 30, 2021	Jun. 30, 2021	Dec. 31, 2020	Sep. 30, 2020	Jun. 30, 2020
Schedule Of Equity Method Investments [Line Items]
Current assets	$ 351,320		$ 352,773
Total assets	475,501		480,098
LIABILITIES AND STOCKHOLDERS' EQUITY
Current liabilities	204,388		192,359
Stockholder's equity	50,994	$ 45,765	68,840	$ 77,778	$ 67,440	$ 63,635
Total liabilities and stockholders' equity	$ 475,501		$ 480,098
CNNC Accuray (Tianjin) Medical Technology Co. Ltd.
Schedule Of Equity Method Investments [Line Items]
Current assets		59,250			22,480
Non current assets		22,677			19,476
Total assets		81,927			41,956
LIABILITIES AND STOCKHOLDERS' EQUITY
Current liabilities		53,700			12,334
Non current liabilities		1,147			1,260
Stockholder's equity		27,080			28,362
Total liabilities and stockholders' equity		$ 81,927			$ 41,956