CONSOLIDATED STATEMENTS OF STOCKHOLDERS' EQUITY - USD ($) $ in Thousands	Total	Common Stock	Additional Paid-In Capital	Accumulated Deficit	Accumulated Other Comprehensive Income (Loss)
Beginning Balance (in shares) at Sep. 30, 2019		40,367,000
Beginning Balance at Sep. 30, 2019	$ 107,333	$ 40	$ 132,160	$ (20,806)	$ (4,061)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Exercise of stock options (in shares)		24,000
Exercise of stock options	73		73
Settlement of restricted stock units (in shares)		474,000
Settlement of restricted stock units	0	$ 1	(1)
Stock-based compensation expense	2,303		2,303
Components of other comprehensive loss:
Net income	560			560
Foreign currency translation adjustment	1,253				1,253
Unrealized gain (loss) on investments	2				2
Other comprehensive income	1,815
Ending Balance (in shares) at Dec. 31, 2019		40,865,000
Ending Balance at Dec. 31, 2019	$ 111,524	$ 41	134,535	(20,246)	(2,806)
Beginning Balance (in shares) at Sep. 30, 2020	41,779,853	41,780,000
Beginning Balance at Sep. 30, 2020	$ 132,243	$ 42	146,518	(13,994)	(323)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Exercise of stock options (in shares)	241,490	241,000
Exercise of stock options	$ 1,889		1,889
Settlement of restricted stock units (in shares)		647,000
Settlement of restricted stock units	0	$ 1	(1)
Stock-based compensation expense	2,747		2,747
Components of other comprehensive loss:
Net income	2,167			2,167
Foreign currency translation adjustment	2,760				2,760
Unrealized gain (loss) on investments	(53)				(53)
Other comprehensive income	$ 4,874
Ending Balance (in shares) at Dec. 31, 2020	42,668,376	42,668,000
Ending Balance at Dec. 31, 2020	$ 141,753	$ 43	$ 151,153	$ (11,827)	$ 2,384