Revenue

6 Months Ended

Mar. 31, 2020

Revenue from Contract with Customer [Abstract]

Revenue Disaggregation

The following table summarizes our revenue by geographic location of our customers:



	Three months ended March 31,				Six months ended March 31,
($ in thousands)	2020		2019		2020		2019
North America, primarily the United States	$	57,374	$	48,869	$	104,910	$	95,204
Europe, Middle East & Africa	9,885		10,764		18,401		20,868
Rest of world	6,188		6,131		12,453		12,005
Total revenue	$	73,447	$	65,764	$	135,764	$	128,077

10. REVENUE (CONTINUED)

The following table summarizes our revenue by the timing of revenue recognition:



	Three months ended March 31,				Six months ended March 31,
($ in thousands)	2020		2019		2020		2019
Transferred at a point in time	$	66,765	$	60,725	$	123,065	$	118,188
Transferred over time	6,682		5,039		12,699		9,889
Total revenue	$	73,447	$	65,764	$	135,764	$	128,077

Contract Balances

Contract Assets

Contract assets consist of subscriber assets. These subscriber assets relate to fees in certain contracts that we charge our customers so they can begin using equipment. In these cases, we retain the ownership of the equipment that the customer uses. The total net book value of subscriber assets of $2.2 million and $2.1 million as of March 31, 2020 and September 30, 2019, respectively, are included in property, equipment and improvements, net. Depreciation expense for these subscriber assets, which is included in cost of sales, was $0.3 million and $0.2 million for the three month periods ended March 31, 2020 and March 31, 2019, respectively and $0.7 million and $0.4 million for the six month periods ended March 31, 2020 and March 31, 2019, respectively. We depreciate the cost of this equipment over its useful life (typically three years).

Contract Liabilities

The timing of revenue recognition may differ from the timing of invoicing to customers. Customers are invoiced for subscription services in advance on a monthly, quarterly or annual basis. Contract liabilities consist of unearned revenue related to annual or multi-year contracts for subscription services and related implementation fees. These pertain to our IoT Solutions segment and our Digi Remote Manager^® services in our IoT Products & Services segment.

Changes in unearned revenue were:



($ in thousands)	Six months ended March 31, 2020
Unearned revenue, beginning of period	$	5,025
Billings	19,553
Revenue recognized	(15,876		)
Unearned revenue, end of period	$	8,702

Remaining Transaction Price

Transaction price allocated to the remaining performance obligations represents contracted revenue that has not been recognized. This includes unearned revenue and unbilled amounts that will be recognized as revenue in future periods. As of March 31, 2020, approximately $13.1 million of revenue is expected to be recognized from remaining performance obligations for subscription contracts. We expect to recognize revenue on approximately $9.0 million of remaining performance obligations over the next twelve months. Revenue from the remaining performance obligations we expect to recognize over a range of two to seven years.