Property and equipment, net consisted of the following (in thousands):


	September 30, 2022			December 31, 2021
Laboratory equipment	$	1,688		$	2,659
Software and computer equipment		559			548
Machinery and equipment		653			1,809
Furniture and fixtures		108			211
Vehicles		333			417
Leasehold improvements		2,203			2,306
Property and equipment, gross		5,544			7,950
Less: accumulated depreciation and amortization		(4,696	)		(5,659	)
Property and equipment, net	$	848		$	2,291

Depreciation expense was $354,000 and $737,000 for the nine months ended September 30, 2022 and 2021, respectively.

As of September 30, 2022, and December 31, 2021, respectively, there was $10,000 and $267,000 of construction in progress included in property and equipment that had not been placed into service and was not subject to depreciation.

Property and equipment are considered assets held for sale when management approves and commits to a plan to dispose of a property or group of properties. The property and equipment held for sale prior to the sale date is separately presented, within current assets, on the condensed consolidated balance sheet as assets held for sale.

During the three and nine months ended September 30, 2022, management initiated the sale of property and equipment related to the Davis laboratory and Archipelago. The Company completed the sale of such property and equipment with a gain on sale of property and equipment in the amount of $0 and $386,000 recorded on the condensed consolidated statements of operations and comprehensive

loss during the three and nine months ended September 30, 2022, respectively. The proceeds related to the sale of property and equipment during the three and nine months ended September 30, 2022 are $5,000 and $897,000, respectively. The Company had no sales of assets held for sale during the three and nine months ended September 30, 2021. Property and equipment related to Archipelago, in the amount of $254,000, have been classified as assets held for sale, and are recorded at fair value as of September 30, 2022. The fair value has been estimated using publicly available prices for some of the assets, and business partners' estimates for assets with prices not readily available, due to the relatively small size of the industry in which they can be used.

During the three and nine months ended September 30, 2022, the Company recorded write-downs of property and equipment of $24,000 and $370,000, respectively. During the nine months ended September 30, 2022, write-downs of $320,000 were related to the Radiance Beauty licensing agreement. See Note 6 for further discussion of the licensing agreement. During the three and nine months ended September 30, 2021, the Company recorded a write-down of property and equipment related to Archipelago in the amount of $1.1 million and $1.3 million, respectively.