STOCK-BASED COMPENSATION - Expense (Details) - USD ($) $ in Thousands, shares in Millions	3 Months Ended	9 Months Ended
Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020
Employee Stock Purchase Plan 2016 [Member]
Discount from market price (as a percent)			15.00%
Allocated share-based compensation expense	$ 28	$ 32	$ 93	$ 118
Stock-based compensation shares available	0.2		0.2
Stock Incentive Plan 2008 [Member]
Allocated share-based compensation expense	$ 2,780	2,351	$ 7,428	10,425
Stock-based compensation shares available	0.6		0.6
Cost of sales [Member] \| Employee Stock Purchase Plan 2016 [Member]
Allocated share-based compensation expense	$ 3	3	$ 11	14
Cost of sales [Member] \| Stock Incentive Plan 2008 [Member]
Allocated share-based compensation expense	2	34	4	93
Research and development Expense [Member] \| Employee Stock Purchase Plan 2016 [Member]
Allocated share-based compensation expense	5	6	16	25
Research and development Expense [Member] \| Stock Incentive Plan 2008 [Member]
Allocated share-based compensation expense	144	117	407	450
Selling, general and administrative Expenses [Member] \| Employee Stock Purchase Plan 2016 [Member]
Allocated share-based compensation expense	20	23	66	79
Selling, general and administrative Expenses [Member] \| Stock Incentive Plan 2008 [Member]
Allocated share-based compensation expense	$ 2,634	$ 2,200	$ 7,017	$ 9,882

Amount of expense for award under share-based payment arrangement. Excludes amount capitalized.

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Discount rate from fair value on purchase date that participants pay for shares.

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The difference between the maximum number of shares (or other type of equity) authorized for issuance under the plan (including the effects of amendments and adjustments), and the sum of: 1) the number of shares (or other type of equity) already issued upon exercise of options or other equity-based awards under the plan; and 2) shares (or other type of equity) reserved for issuance on granting of outstanding awards, net of cancellations and forfeitures, if applicable.

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