Discontinued Operations - Financial Results (Details) - USD ($) $ in Thousands	3 Months Ended	6 Months Ended
Mar. 31, 2020	Mar. 31, 2019	Mar. 31, 2020	Mar. 31, 2019
Disposal Group, Including Discontinued Operation, Income Statement Disclosures [Abstract]
Net (loss) income	$ (65)	$ 6,250	$ (182)	$ 14,399
Discontinued Operations, Held-for-sale \| Semiconductor Cryogenics Business
Disposal Group, Including Discontinued Operation, Income Statement Disclosures [Abstract]
Total revenue		35,654		74,978
Total cost of revenue		21,860		44,425
Gross profit		13,794		30,553
Research and development		2,168		4,326
Selling, general and administrative	86	4,993	(171)	12,196
Total operating expenses	86	7,161	(171)	16,522
Operating income	(86)	6,633	171	14,031
Other (loss) income, net		278	(410)	567
(Loss) income before income taxes and earnings of equity method investment	(86)	6,911	(239)	14,598
Income tax (benefit) provision	(21)	1,930	(57)	3,240
(Loss) income before equity in earnings of equity method investment	(65)	4,981	(182)	11,358
Equity in earnings of equity method investment		1,269		3,041
Net (loss) income	$ (65)	6,250	$ (182)	14,399
Discontinued Operations, Held-for-sale \| Semiconductor Cryogenics Business \| Products
Disposal Group, Including Discontinued Operation, Income Statement Disclosures [Abstract]
Total revenue		23,895		52,681
Total cost of revenue		15,182		31,698
Discontinued Operations, Held-for-sale \| Semiconductor Cryogenics Business \| Services
Disposal Group, Including Discontinued Operation, Income Statement Disclosures [Abstract]
Total revenue		11,759		22,297
Total cost of revenue		$ 6,678		$ 12,727

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Amount of tax expense (benefit) related to a discontinued operation. Includes, but is not limited to, tax expense (benefit) related to income (loss) from operations during the phase-out period, tax expense (benefit) related to gain (loss) on disposal, tax expense (benefit) related to gain (loss) for reversal of write-down (write-down) to fair value, less cost to sell, and tax expense (benefit) related to adjustments of a prior period gain (loss) on disposal.

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