Intangible Assets

6 Months Ended

Mar. 31, 2021

Goodwill and Intangible Assets Disclosure [Abstract]

The gross and net carrying values of intangible assets as of the balance sheet dates, by major intangible asset class are as follows (in millions):


	March 31, 2021						September 30, 2020
	Gross Amount		Accumulated Amortization		Net Amount		Gross Amount		Accumulated Amortization		Net Amount
Intangible assets subject to amortization
Trade/domain names	$	3.7	$	(0.5)	$	3.2	$	3.7	$	(0.2)	$	3.5
Software programs/platforms	29.0		(9.1)		19.9		29.0		(4.9)		24.1
Customer base	38.2		(19.2)		19.0		38.2		(16.3)		21.9
Total intangible assets subject to amortization	70.9		(28.8)		42.1		70.9		(21.4)		49.5

Intangible assets not subject to amortization
Website domains	2.1		—		2.1		2.1		—		2.1
Business licenses	3.8		—		3.8		3.2		—		3.2
Total intangible assets not subject to amortization	5.9		—		5.9		5.3		—		5.3
Total intangible assets	$	76.8	$	(28.8)	$	48.0	$	76.2	$	(21.4)	$	54.8

Amortization expense related to intangible assets was $3.7 million and $1.1 million for the three months ended March 31, 2021 and 2020, respectively. Amortization expense related to intangibles assets was $7.5 million and $1.9 million for the six months ended March 31, 2021 and 2020, respectively.

As of March 31, 2021, the estimated future amortization expense was as follows:


(in millions)
Fiscal 2021 (remaining six months)	$	7.6
Fiscal 2022	13.9
Fiscal 2023	12.2
Fiscal 2024	4.7
Fiscal 2025 and thereafter	3.7
Total intangible assets subject to amortization	$	42.1