As of December 31, 2021, the Company had restricted cash of $4.2 million held as letters of credit issued by an FDIC-insured financial institution as security deposits, as required under the Company’s 4 Hartwell Place and 35 CambridgePark Drive lease agreements. As of December 31, 2021, and 2020, all restricted cash was classified as a non-current asset because the associated lease terms expired more than 12 months from the respective consolidated balance sheet date, respectively.