CONVERTIBLE NOTES AND OTHER DEBTS - Other (Details) - USD ($) $ in Thousands	12 Months Ended
Dec. 31, 2021	Dec. 31, 2020
Debt Instrument [Line Items]
Financing from French government agencies related to various government incentive programs	$ 12,259	$ 14,974
Relief loans	5,651	6,694
Term loans	$ 71	$ 167
Finance Lease, Liability, Noncurrent, Statement of Financial Position [Extensible Enumeration]	Long-term portion	Long-term portion
Obligations under finance leases	$ 0	$ 22
Total debt obligations	17,981	21,857
Less: current portion	(4,992)	(11,771)
Long-term portion	12,989	10,086
Loans payable to bank	$ 12,259	$ 14,974
TVN \| Loans Backed By French Research And Development Tax Credit Receivables
Debt Instrument [Line Items]
Basis spread on variable rate (as a percent)	1.90%

Percentage points added to the reference rate to compute the variable rate on the debt instrument.

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Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

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No definition available.

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Present value of lessee's discounted obligation for lease payments from finance lease, classified as noncurrent.

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Indicates line item in statement of financial position that includes noncurrent finance lease liability.

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Including the current and noncurrent portions, aggregate carrying value as of the balance sheet date of loans payable (with maturities initially due after one year or beyond the operating cycle if longer).

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Carrying value as of the balance sheet date of portion of long-term loans payable due within one year or the operating cycle if longer.

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Including the current and noncurrent portions, carrying value as of the balance sheet date of loans from a bank with maturities initially due after one year or beyond the normal operating cycle if longer.

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Carrying value as of the balance sheet date of loans payable (with maturities initially due after one year or beyond the operating cycle if longer), excluding current portion.

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The carrying amount as of the balance sheet date for the aggregate of other miscellaneous borrowings owed by the reporting entity.

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Amount of long-term loans payable classified as other.

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