Joint Venture - Additional Information (Details) - USD ($)	3 Months Ended		6 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2020	Dec. 31, 2019	Jun. 30, 2020	Jun. 30, 2019	Jan. 31, 2019
Schedule Of Equity Method Investments [Line Items]
Gain on contribution to joint venture				$ 12,964,000
Accumulated deficit	$ (476,542,000)		$ (476,542,000)		$ (481,713,000)
Goodwill	57,963,000		57,963,000		57,717,000	$ 57,770,000
Impairment of goodwill	0
Accuray Asia
Schedule Of Equity Method Investments [Line Items]
Percentage of ownership interest in joint venture							49.00%
Gain on contribution to joint venture		$ 13,000,000.0
Non cash revenue recognized from joint venture	1,400,000		1,400,000
Joint venture associated costs	200,000		200,000
Deferred of intra-entity profit margin	1,300,000		1,300,000		$ 1,800,000
Previously deferred intra-entity margin from system sales	600,000		1,500,000
Deferral of intra entity margin from system sales	300,000		900,000
Accumulated deficit	900,000		900,000
Equity method investment	17,000,000.0		17,000,000.0
Proportional share of underlying equity in net assets	13,800,000		13,800,000
Equity method investment, intra-entity profit			1,300,000
Goodwill	$ 4,500,000		4,500,000
Impairment of goodwill			$ 0