Joint Venture - Summary of Financial Information of Joint Ventures (Operations Data) (Details) - USD ($) $ in Thousands	3 Months Ended								6 Months Ended	12 Months Ended
	Jun. 30, 2021	Mar. 31, 2021	Dec. 31, 2020	Sep. 30, 2020	Jun. 30, 2020	Mar. 31, 2020	Dec. 31, 2019	Sep. 30, 2019	Mar. 31, 2020	Jun. 30, 2021	Mar. 31, 2021	Jun. 30, 2020	Jun. 30, 2019
Schedule Of Equity Method Investments [Line Items]
Total net revenue	$ 110,936	$ 102,562	$ 97,456	$ 85,332	$ 94,977	$ 99,548	$ 98,826	$ 89,577		$ 396,289		$ 382,928	$ 418,785
Gross Profit	43,731	39,542	40,831	35,403	39,745	39,133	37,900	32,943		159,507		149,721	162,651
Net income (loss)	$ (11,092)	$ (390)	$ 4,769	$ 402	$ (152)	$ 2,625	$ 10,710	$ (9,356)		$ (6,311)		$ 3,827	$ (16,430)
CNNC Accuray (Tianjin) Medical Technology Co. Ltd.
Schedule Of Equity Method Investments [Line Items]
Total net revenue									$ 13,764		$ 33,054
Gross Profit									2,960		10,578
Net income (loss)									(306)		1,785
Net income (loss) attributable to the Company									$ (149)		$ 872