Business Segment Information (Details) $ in Thousands	3 Months Ended		9 Months Ended
	Jun. 30, 2017 USD ($)	Jun. 30, 2016 USD ($)	Jun. 30, 2017 USD ($) segment	Jun. 30, 2016 USD ($)	Sep. 30, 2016 USD ($)
Segment Reporting Information [Line Items]
Number of business segments | segment			3
Net revenues	$ 47,760	$ 33,342	$ 109,839	$ 77,899
Operating income (loss)	3,971	(602)	2,388	(8,137)
Identifiable assets	148,439		$ 148,439		$ 118,430
Product Concentration Risk | Sales Revenue, Product Line | Semiconductor
Segment Reporting Information [Line Items]
Concentration risk, percentage (less than)			25.00%
Operating Segments | Solar
Segment Reporting Information [Line Items]
Net revenues	28,981	19,001	$ 56,960	38,346
Operating income (loss)	2,991	(402)	90	(4,532)
Identifiable assets	69,935		69,935		42,962
Operating Segments | Semiconductor
Segment Reporting Information [Line Items]
Net revenues	15,951	12,200	45,097	33,406
Operating income (loss)	2,250	1,056	6,013	777
Identifiable assets	56,208		56,208		51,985
Operating Segments | Polishing
Segment Reporting Information [Line Items]
Net revenues	2,828	2,141	7,782	6,147
Operating income (loss)	738	343	1,705	899
Identifiable assets	4,510		4,510		4,819
Non-Segment
Segment Reporting Information [Line Items]
Operating income (loss)	(2,008)	$ (1,599)	(5,420)	$ (5,281)
Identifiable assets	$ 17,786		$ 17,786		$ 18,664