Prepaid and other current assets consisted of the following as of March 31, 2023, and December 31, 2022 (in thousands):


	March 31,		December 31,
	2023		2022
Down payments for inventory	$	7,649	$	13,987
Prepaid research and development		16,469		15,181
Other prepaid expenses		12,441		7,182
Total prepaid expenses	$	36,559	$	36,350


	March 31,		December 31,
	2023		2022
Royalties receivable	$	1,597	$	1,442
ERC credit		8,711		8,711
Receivable from collaboration agreement		15,000		20,000
Deposits and other current assets		9,041		6,505
Total other current assets	$	34,349	$	36,658

Under the provisions of the Coronavirus Aid, Relief, and Economic Security Act (the “CARES Act”) signed into law on March 27, 2020 and the subsequent extension of the CARES Act, the Company was eligible for a refundable employee retention credit (“ERC”) subject to certain criteria. The ERC provides eligible employers with less than 500 employees a refundable tax credit against the employer’s share of social security taxes. The ERC is equal to 70% of qualified wages paid to employees during calendar year 2021 for a maximum credit of $7,000 per employee for each calendar quarter through September 30, 2021. In November 2022, the Company filed for an $8.7 million refund under the CARES Act relating to the ERC. The Company expects receipt of the ERC refund during 2023, and this amount is included in other current assets on the consolidated balance sheet as of March 31, 2023 and December 31, 2022, respectively.