18.	TRADE AND OTHER RECEIVABLES

	December 31, 2020 US$‘000		December 31, 2019 US$‘000
Trade receivables, net of impairment losses		20,025		17,754
Prepayments		1,159		576
Contract assets		1,177		2,317
Value added tax		92		59
Finance lease receivables		215		281

		22,668		20,987

Trade receivables are shown net of an impairment losses provision of US$3,922,000 (2019: US$5,443,000) (see Note 29). Prepayments are shown net of impairment of US$562,000 (2019: US$1,376,000) (see Note 7).

Contract assets have decreased compared to the prior year as the Group shipped less product to customers with cost per test contracts in the last part of the year.

Long-term contract receivable

(i) Finance lease commitments – Group as lessor

The Group leases instruments as part of its business. Future minimum receivables with non-cancellable terms are as follows:

	December 31, 2020 US$‘000
	Gross investment		Unearned income		Minimum payments receivable
Less than one year		415		200		215
Between one and five years (Note 16)		591		300		291

		1,006		500		506

	December 31, 2019 US$‘000
	Gross investment		Unearned income		Minimum payments receivable
Less than one year		523		242		281
Between one and five years (Note 16)		805		402		403

		1,328		644		684

The Group classified future minimum lease receivables between one and five years of US$291,000 (2019: US$403,000) as Other Assets, see Note 16. Under the terms of the lease arrangements, no contingent rents are receivable.

(ii) Operating lease commitments – Group as lessor

The Group leases instruments under operating leases as part of its business.

Future minimum rentals receivable under non-cancellable operating leases are as follows:

	December 31, 2020 US$‘000
	Instruments		Total
Less than one year		2,767		2,767
Between one and five years		171		171

		2,938		2,938

	December 31, 2019 US$‘000
	Instruments		Total
Less than one year		3,528		3,528
Between one and five years		27		27

		3,555		3,555