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, 2017		33,724,000
Beginning Balance at Sep. 30, 2017	$ 61,408	$ 34	$ 78,677	$ (17,450)	$ 147
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Exercise of stock options (in shares)		63,000
Exercise of stock options	137		137
Settlement of restricted stock units (in shares)		450,000
Settlement of restricted stock units	0
Acquisition-related shares issued (in shares)		666,000
Acquisition-related shares issued	5,608	$ 1	5,607
Stock-based compensation expense	1,889		1,889
Amortization of closing shares	710		710
Components of other comprehensive loss:
Net loss	(5,736)			(5,736)
Currency translation adjustment	189				189
Change in unrealized gain on investments	(59)				(59)
Total other comprehensive loss	(5,606)
Ending Balance (in shares) at Dec. 31, 2017		34,903,000
Ending Balance at Dec. 31, 2017	$ 72,401	$ 35	87,020	(14,931)	277
Beginning Balance (in shares) at Sep. 30, 2018	37,961,224	37,961,000
Beginning Balance at Sep. 30, 2018	$ 95,394	$ 38	116,944	(21,002)	(586)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Exercise of stock options (in shares)	134,727	135,000
Exercise of stock options	$ 586		586
Settlement of restricted stock units (in shares)		543,000
Settlement of restricted stock units		$ 1	(1)
Stock-based compensation expense	2,670		2,670
Components of other comprehensive loss:
Net loss	(3,191)			(3,191)
Currency translation adjustment	(824)				(824)
Change in unrealized gain on investments	13				13
Total other comprehensive loss	$ (4,002)
Ending Balance (in shares) at Dec. 31, 2018	38,638,816	38,639,000
Ending Balance at Dec. 31, 2018	$ 95,568	$ 39	$ 120,199	$ (23,273)	$ (1,397)