Equity Method Investments - Additional information (Detail) (USD $)	12 Months Ended
	Sep. 30, 2014	Sep. 30, 2013	Sep. 30, 2012
Schedule of Equity Method Investments [Line Items]
Equity in earnings of equity method investments	$ 1,235,000	$ 2,442,000	$ 2,133,000
Equity method investments	28,944,000	25,687,000
BioCision, LLC
Schedule of Equity Method Investments [Line Items]
Joint venture interest, percentage	22.00%
Equity investment cost	4,000,000
Equity in earnings of equity method investments	300,000
Equity method investments	3,700,000
ULVAC Cryogenics, Inc.
Schedule of Equity Method Investments [Line Items]
Joint venture interest, percentage	50.00%
Equity in earnings of equity method investments	1,600,000	2,600,000	2,000,000
Equity method investments	22,600,000	22,700,000
Management fee payments received	600,000	600,000	1,000,000
Charges for products or services	400,000	500,000	800,000
Accounts payable for unpaid products and services	79,000	26,000
Cash dividend received	900,000	5,000,000
Yaskawa Brooks Automation, Inc.
Schedule of Equity Method Investments [Line Items]
Joint venture interest, percentage	50.00%
Equity in earnings of equity method investments	(100,000)	(200,000)	100,000
Equity method investments	2,600,000	3,000,000
Charges for products or services	700,000	500,000	500,000
Accounts payable for unpaid products and services	133,000	47,000
Revenues earned from joint ventures	7,400,000	6,300,000	8,000,000
Due from joint venture	$ 2,100,000	$ 2,300,000