Geographic Regions (Details) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Sep. 30, 2021	Jun. 30, 2021	Mar. 31, 2021	Dec. 31, 2020	Sep. 30, 2020	Jun. 30, 2020	Mar. 31, 2020	Dec. 31, 2019	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2019
Revenues from External Customers and Long-Lived Assets [Line Items]
Net revenue									$ 85,205	$ 65,463	$ 85,035
Operating income (loss)	$ 1,296	$ 1,204	$ 171	$ 1,054	$ (1,181)	$ 31	$ (972)	$ 1,637	3,725	(485)	4,916
Net long-lived assets	14,083								14,083
United States
Revenues from External Customers and Long-Lived Assets [Line Items]
Net revenue									58,937	48,089	65,942
Operating income (loss)									(4,174)	(5,814)	726
Net long-lived assets	11,990				11,804				11,990	11,804
China
Revenues from External Customers and Long-Lived Assets [Line Items]
Net revenue									22,828	13,510	9,500
Operating income (loss)									6,958	4,744	3,686
Net long-lived assets	$ 2,093				191				2,093	191
Other
Revenues from External Customers and Long-Lived Assets [Line Items]
Net revenue									3,440	3,864	9,593
Operating income (loss)									$ 941	585	$ 504
Net long-lived assets					$ 11,995					$ 11,995