Stockholders' Equity - Schedule of Stockholders' Equity (Details) - USD ($) $ in Thousands	3 Months Ended						9 Months Ended
	Jun. 30, 2021	Mar. 31, 2021	Dec. 31, 2020	Jun. 30, 2020	Mar. 31, 2020	Dec. 31, 2019	Jun. 30, 2021	Jun. 30, 2020
Increase (Decrease) in Stockholders' Equity
Balance	$ 106,938	$ 115,063	$ 111,815	$ 108,112	$ 112,437	$ 116,175	$ 111,815	$ 116,175
Net income (loss)	8,419	5,260	4,514	213	(4,238)	(5,196)	18,193	(9,221)
Exercise of stock options, grants of restricted stock awards, and vesting of restricted stock units		155	197	1	32	2
Taxes paid associated with net settlement of stock compensation awards	(343)	(3,145)	(57)	(6)	(60)	(498)
Stock compensation expense	1,525			1,494	1,244	1,121	4,848	3,860
Foreign currency translation				424	(1,303)	833
Balance	$ 116,561	$ 106,938	$ 115,063	$ 110,238	$ 108,112	$ 112,437	$ 116,561	$ 110,238
Common Stock
Increase (Decrease) in Stockholders' Equity
Balance (in shares)	35,115,307	34,212,815	34,082,406	33,988,798	33,887,591	33,687,115	34,082,406	33,687,115
Balance	$ 35	$ 34	$ 34	$ 34	$ 34	$ 34	$ 34	$ 34
Exercise of stock options, grants of restricted stock awards, and vesting of restricted stock units (in shares)	318,242	1,079,955	151,845	34,185	111,272	283,164
Exercise of stock options, grants of restricted stock awards, and vesting of restricted stock units		$ 1
Taxes paid associated with net settlement of stock compensation awards (in shares)	(15,834)	(177,463)	(7,703)	(1,210)	(10,065)	(67,688)
Forfeiture of restricted stock awards (in shares)			(13,733)			(15,000)
Balance (in shares)	35,417,715	35,115,307	34,212,815	34,021,773	33,988,798	33,887,591	35,417,715	34,021,773
Balance	$ 35	$ 35	$ 34	$ 34	$ 34	$ 34	$ 35	$ 34
Additional Paid-in Capital
Increase (Decrease) in Stockholders' Equity
Balance	249,866	250,002	247,892	244,527	243,311	242,686	247,892	242,686
Exercise of stock options, grants of restricted stock awards, and vesting of restricted stock units		154	197	1	32	2
Taxes paid associated with net settlement of stock compensation awards	(343)	(3,145)	(57)	(6)	(60)	(498)
Stock compensation expense				1,494	1,244	1,121
Balance	251,048	249,866	250,002	246,016	244,527	243,311	251,048	246,016
Accumulated Other Comprehensive Loss
Increase (Decrease) in Stockholders' Equity
Balance	(8,763)	(8,886)	(9,782)	(8,443)	(7,140)	(7,973)	(9,782)	(7,973)
Foreign currency translation				424	(1,303)	833
Balance	(8,740)	(8,763)	(8,886)	(8,019)	(8,443)	(7,140)	(8,740)	(8,019)
Accumulated Deficit
Increase (Decrease) in Stockholders' Equity
Balance	(112,572)	(117,832)	(122,346)	(128,006)	(123,768)	(118,572)	(122,346)	(118,572)
Net income (loss)	8,419	5,260	4,514	213	(4,238)	(5,196)
Balance	$ (104,154)	$ (112,572)	$ (117,832)	$ (127,793)	$ (128,006)	$ (123,768)	$ (104,154)	$ (127,793)