A savings certificate entitling the Entity (that is, bearer) to receive interest at an established maturity date, based upon a fixed interest rate. A certificate of deposit may be issued in any denomination. Certificates of deposit are generally issued by commercial banks and, therefore, insured by the FDIC (up to the prescribed limit). Certificates of deposit generally restrict holders from withdrawing funds on demand without the incurrence of penalties. Generally, only certificates of deposit with original maturities of three months or less qualify as cash equivalents. Original maturity means original maturity to the entity holding the investment. As a related example, both a three-month US Treasury bill and a three-year Treasury note purchased three months from maturity qualify as cash equivalents. However, a Treasury note purchased three-years ago does not become a cash equivalent when its remaining maturity is three months.

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Commitments and Contingencies, Operating Leases (Details) - USD ($) $ in Thousands		3 Months Ended		6 Months Ended
	Mar. 26, 2021	Jun. 30, 2021	Jun. 30, 2020	Jun. 30, 2021	Jun. 30, 2020	Dec. 31, 2020	Jun. 07, 2018
Operating Leases [Abstract]
Rent expense		$ 300	$ 300	$ 600	$ 500
Restricted cash		$ 1,334		$ 1,334		$ 1,568
ESB Lease Agreement [Member]
Operating Leases [Abstract]
Term of lease agreement		3 years		3 years
Letter of credit							$ 900
Lease expiration date				Aug. 29, 2024
Certificate of deposit		$ 800		$ 800		900
ESB Lease Agreement Amendment [Member]
Operating Leases [Abstract]
Letter of credit		800		$ 800
Lease expiration date	Jun. 30, 2024
Operating lease right of use asset, adjustment	$ 1,100
Inotek Lexington Massachusetts Lease Agreement [Member]
Operating Leases [Abstract]
Lease expiration date				Feb. 28, 2023
Rental income received under sublease agreement		100	$ 100	$ 200	$ 200
Operating and Finance Leases [Member]
Operating Leases [Abstract]
Restricted cash		$ 1,000		$ 1,000		$ 1,100