Research and development costs consist of personnel and related expenses for technology and product development, depreciation and amortization, laboratory supplies, consulting services, computer costs and data storage fees paid to hosting providers related to research and development and allocated overhead costs. These costs are stated net of government grants for research and development and innovation received as tax credits and net of capitalized costs.

Government grants for research and development and innovation received as tax credits

The Company receives government grants in France for research and development and innovation by way of tax credits. Total government grants for research and development and innovation recognized in the statement of loss amounts to $0.4 million, $0.8 million, $0.4 million for the years ended December 31, 2021, December 31, 2020, and December 31, 2019, respectively. There are no unfulfilled conditions or other contingencies attached to these grants. Refer to the Note 24 – “Borrowings” for additional discussion on COVID loans.

Selling and marketing costs consist of personnel and related expenses for the employees of the sales and marketing organization, costs of communications materials that are produced to generate greater awareness and utilization of the platform among customers, costs of third-party market research, costs related to transportation and distribution of our products, and allocated overhead costs. These costs are stated net of government grants under the US Paycheck Protection Program (“PPP”) for payroll and/or rental obligations received as a loan that is forgiven if utilized as intended.

The Company pays sales commission to its employees for obtaining contracts. These costs are expensed as part of employee compensation in selling and marketing costs. They are not capitalized as contract costs as the commissions either represent bonuses payable for revenue earned in the period or have a service condition attached.

General and administrative costs consist of personnel and related expenses for our executive, accounting and finance, legal, quality, support and human resources functions, depreciation and amortization, professional services fees incurred by these functions, general corporate costs and allocated overhead costs, which include occupancy costs and information technology costs.

	For the year ended December 31,
	2021			2020			2019
Changes in inventories of finished goods and work in progress	$	568		$	(259	)	$	729
Raw materials and consumables used		(9,650	)		(3,843	)		(3,180	)
Employee benefit expenses		(53,802	)		(36,732	)		(27,237	)
Social charges		(8,373	)		(6,983	)		(4,218	)
COVID—salaries reimbursement		—			1,129			—
Research tax credit		1,597			763			447
Share-based compensation		(8,514	)		(1,359	)		(717	)
Depreciation		(2,517	)		(1,758	)		(1,546	)
Amortization		(1,092	)		(632	)		(367	)
Professional fees		(11,318	)		(5,371	)		(5,357	)
Office expenses		(5,333	)		(2,006	)		(2,774	)
Travel		(1,576	)		(1,361	)		(4,416	)
Marketing		—			(972	)		(1,761	)
Licenses		(2,021	)		(1,647	)		(996	)
Less: capitalized software development costs ("Note 17 - Intangible assets”)		3,858			2,436			—
Other expense		(13,874	)		(7,099	)		(6,240	)
Total	$	(112,047	)	$	(65,694	)	$	(57,633	)

Depreciation and amortization have been charged in the following expense categories (in USD thousands):

	For the year ended December 31,
	2021						2020						2019
	Depreciation			Amortization			Depreciation			Amortization			Depreciation			Amortization
Cost of revenue	$	—		$	(483	)	$	—		$	(111	)	$	—		$	—
Research and development costs		(1,028	)		—			(727	)		—			(624	)		—
Selling and marketing costs		(744	)		—			(543	)		—			(550	)		—
General and administrative costs		(745	)		(609	)		(488	)		(521	)		(372	)		(367	)
Total	$	(2,517	)	$	(1,092	)	$	(1,758	)	$	(632	)	$	(1,546	)	$	(367	)

The table presents employee costs by function, which consists of “Employee benefit expenses”, “Social charges” and “Share-based compensation” from the operating expense table (in USD thousands):

	For the year ended December 31,
	2021		2020		2019
Research and development costs	$	23,899	$	16,109	$	10,622
Selling and marketing costs		21,659		12,085		10,579
General and administrative costs		25,131		16,880		10,244
Total	$	70,689	$	45,074	$	31,445