ORGANIZATION AND NATURE OF BUSINESS; BASIS OF PRESENTATION; PRINCIPLES OF CONSOLIDATION; SIGNIFICANT ACCOUNTING POLICIES - Narrative (Details)							3 Months Ended		6 Months Ended
	Jul. 11, 2023	Jul. 07, 2023 USD ($) shares	Jun. 09, 2023 USD ($) shares	Apr. 21, 2023 USD ($)	Mar. 13, 2023	Aug. 15, 2022 USD ($)	Jun. 30, 2023 USD ($)	Jun. 30, 2022 USD ($)	Jun. 30, 2023 USD ($)	Jun. 30, 2022 USD ($)	Mar. 15, 2023	Dec. 31, 2022 USD ($)	Mar. 21, 2022	Mar. 27, 2018 USD ($)
Property, Plant and Equipment [Line Items]
Accumulated deficit							$ (656,769,000)		$ (656,769,000)			$ (607,239,000)
Net loss							(32,735,000)	$ (18,523,000)	(49,530,000)	$ (31,988,000)
Net cash used in operating activities									24,188,000	25,605,000
Working capital deficit							11,500,000		11,500,000
Cash and cash equivalents and investments							30,700,000		30,700,000			$ 45,600,000
Decrease in cash and cash equivalents and investments									(14,900,000)
Impairment charges							0	0	$ 0	0
Instrument warranty term									1 year
Kits and accessories warranty term									60 days
Pre launch inventory expenses							$ 0	$ 200,000	$ 100,000	$ 300,000
Lease extension							1 year		1 year
Lessor lease term							5 years		5 years
Subsequent Event
Property, Plant and Equipment [Line Items]
Reverse stock split ratio	0.1
Restructuring Support Agreement | Common stock | Plan
Property, Plant and Equipment [Line Items]
Purchase price			$ 10,000,000
Restructuring Support Agreement | Series A Preferred Stock
Property, Plant and Equipment [Line Items]
Conversion of preferred stock into common stock with related party (in shares) | shares			400,000
Schuler Trust | Affiliated Entity | March 2022 Securities Purchase Agreement
Property, Plant and Equipment [Line Items]
Sale of stock (in shares) | shares			500,000
Net proceeds			$ 4,000,000
Schuler Trust | Affiliated Entity | Restructuring Support Agreement
Property, Plant and Equipment [Line Items]
Purchase price			10,000,000
Schuler Trust | Affiliated Entity | Restructuring Support Agreement | Common stock
Property, Plant and Equipment [Line Items]
Purchase price			$ 10,000,000
Liabilities, Outstanding Notes | Lender Concentration Risk | Ad Hoc Noteholder Group
Property, Plant and Equipment [Line Items]
Risk concentration					85.00%
Instruments
Property, Plant and Equipment [Line Items]
Estimated useful life of assets							5 years		5 years
Equipment
Property, Plant and Equipment [Line Items]
Lease term							3 years		3 years
Minimum
Property, Plant and Equipment [Line Items]
Estimated useful life of assets							1 year		1 year
Lease term							2 years		2 years
Maximum
Property, Plant and Equipment [Line Items]
Estimated useful life of assets							7 years		7 years
Lease term							6 years		6 years
2.50% Convertible Notes Due 2023 | Convertible Notes
Property, Plant and Equipment [Line Items]
Interest rate			2.50%	2.50%	2.50%	2.50%	2.50%	2.50%	2.50%	2.50%	2.50%	2.50%	2.50%	2.50%
Aggregate principal amount			$ 10,000,000											$ 150,000,000
Debt outstanding, not converted and in default							$ 700,000		$ 700,000
2.50% Convertible Notes Due 2023 | Convertible Notes | Restructuring Support Agreement
Property, Plant and Equipment [Line Items]
Notes exchanged			$ 55,900,000
5.00% Convertible Notes Due 2026 | Convertible Notes
Property, Plant and Equipment [Line Items]
Interest rate			5.00%				5.00%		5.00%
5.00% Convertible Notes Due 2026 | Convertible Notes | Subsequent Event
Property, Plant and Equipment [Line Items]
Interest rate		5.00%
Aggregate principal amount		$ 700,000
Shares issued (in shares) | shares		100,000
5.00% Convertible Notes Due 2026 | Convertible Notes | Restructuring Support Agreement
Property, Plant and Equipment [Line Items]
Notes exchanged			$ 56,900,000
Aggregate principal amount			10,000,000
Aggregate principal amount			56,900,000
5.0% Secured Promissory Note | Convertible Notes | Schuler Trust | August 2022 Exchange Transaction | Affiliated Entity
Property, Plant and Equipment [Line Items]
Aggregate principal amount						$ 49,900,000
5.0% Secured Promissory Note | Senior Notes | Schuler Trust | Affiliated Entity
Property, Plant and Equipment [Line Items]
Aggregate principal amount			$ 25,400,000
Shares issued (in shares) | shares			3,400,000
5.0% Secured Promissory Note | Senior Notes | Schuler Trust | August 2022 Exchange Transaction | Affiliated Entity
Property, Plant and Equipment [Line Items]
Interest rate						5.00%
Notes exchanged				$ 34,900,000
Aggregate principal amount						$ 34,900,000
Restructuring Support Agreement | Senior Notes | Series A Preferred Stock
Property, Plant and Equipment [Line Items]
Shares issued (in shares) | shares			400,000
Restructuring Support Agreement | Senior Notes | Affiliated Entity
Property, Plant and Equipment [Line Items]
Shares issued (in shares) | shares			3,400,000