LEASES - Narrative (Details)			12 Months Ended
	May 01, 2020 USD ($) lease	Jan. 01, 2019	Dec. 31, 2020 USD ($) lease renewal_option	Dec. 31, 2019 USD ($)
Lessee, Lease, Description [Line Items]
Number of operating lease | lease			2
Number of non-cancelable leases | lease			2
Number of renewal options recognized | renewal_option			0
Weighted average incremental borrowing rate		4.75%
Finance lease liability			$ 205,000
Operating lease cost			1,132,000	$ 1,066,000
Cash paid for operating lease liabilities			$ 613,000	492,000
Lease Amendment
Lessee, Lease, Description [Line Items]
Operating lease renewal periods	3 months
Number of leases amended | lease	1
Base rent deferral period	3 months
Operating expense deferral period			3 months
Lab Equipment Lease
Lessee, Lease, Description [Line Items]
Finance lease term			60 months
Finance lease interest rate			5.99%
Finance lease, right-of-use asset			$ 204,436
Finance lease liability			204,436
Restricted Cash
Lessee, Lease, Description [Line Items]
Collateral pledged amount			105,000
Office Building | Letter of Credit
Lessee, Lease, Description [Line Items]
Security deposit			50,000
Operating lease deposit, letter of credit	$ 200,000		105,000
Line of credit facility, annual step down of no defaults				50,000
Research and Development Expense
Lessee, Lease, Description [Line Items]
Operating lease cost			812,000	803,000
Finance lease, amortization			3,000	0
Selling, General and Administrative Expenses
Lessee, Lease, Description [Line Items]
Operating lease cost			$ 320,000	$ 263,000
Minimum | Facilities
Lessee, Lease, Description [Line Items]
Operating lease renewal periods			2 years
Maximum | Facilities
Lessee, Lease, Description [Line Items]
Operating lease renewal periods			5 years
Maximum | Facilities and Equipment
Lessee, Lease, Description [Line Items]
Operating lease term			12 months