Business Combinations - Additional Information (Details) - USD ($) $ in Thousands			1 Months Ended	12 Months Ended
	May 23, 2018	Oct. 16, 2017	Jan. 31, 2019	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2017	Dec. 06, 2019	Apr. 30, 2018
Business Acquisition [Line Items]
Consideration paid for acquisition, net of cash acquired				$ 0	$ 29,744	$ 0
Acquisition-related contingent consideration				1,601	3,051
Payment for contingent consideration liability				1,030	1,284	$ 0
Revenue from business combinations					9,100
Net loss from business combinations					$ 5,300
A2iA
Business Acquisition [Line Items]
Consideration paid for acquisition, net of cash acquired	$ 26,800
Acquisition-related shares issued (in shares)	2,514,588
Value of common stock issued during acquisition	$ 21,900
Transaction-related liabilities	200
Expenses incurred in connection with acquisition	2,200
Payments for cash for collateral	$ 700
Payments for collateral, equity (in shares)	508,479
Payments for collateral, equity, value	$ 4,400
Period to maintain escrow funds	24 months
ICAR
Business Acquisition [Line Items]
Consideration paid for acquisition, net of cash acquired		$ 3,000
Acquisition-related shares issued (in shares)		584,291
Value of common stock issued during acquisition		$ 5,600
Expenses incurred in connection with acquisition		500
Acquisition-related contingent consideration		2,900
Escrow deposit		1,500						$ 1,500
ICAR | Subsequent Event
Business Acquisition [Line Items]
Escrow deposit							$ 1,000
ICAR | Q4 Consideration
Business Acquisition [Line Items]
Contingent consideration arrangement		1,500
ICAR | Earnout Consideration
Business Acquisition [Line Items]
Contingent consideration arrangement		3,800
Acquisition-related contingent consideration				$ 1,800
Payment for contingent consideration liability			$ 1,800
ICAR | Maximum
Business Acquisition [Line Items]
Aggregate purchase price		$ 13,900