STOCK-BASED COMPENSATION - Expense (Details) - USD ($) $ in Thousands, shares in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2021	Jun. 30, 2020	Jun. 30, 2021	Jun. 30, 2020
Employee Stock Purchase Plan 2016 [Member]
Discount from market price (as a percent)			15.00%
Allocated share-based compensation expense	$ 33	$ 57	$ 65	$ 86
Stock-based compensation shares available	0.2		0.2
Stock Incentive Plan 2008 [Member]
Allocated share-based compensation expense	$ 2,811	5,679	$ 4,648	8,074
Stock-based compensation shares available	0.6		0.6
Cost of sales [Member] | Employee Stock Purchase Plan 2016 [Member]
Allocated share-based compensation expense	$ 4	7	$ 8	11
Cost of sales [Member] | Stock Incentive Plan 2008 [Member]
Allocated share-based compensation expense	2	33	2	59
Research and development Expense [Member] | Employee Stock Purchase Plan 2016 [Member]
Allocated share-based compensation expense	6	12	11	19
Research and development Expense [Member] | Stock Incentive Plan 2008 [Member]
Allocated share-based compensation expense	149	146	263	333
Selling, general and administrative Expenses [Member] | Employee Stock Purchase Plan 2016 [Member]
Allocated share-based compensation expense	23	38	46	56
Selling, general and administrative Expenses [Member] | Stock Incentive Plan 2008 [Member]
Allocated share-based compensation expense	$ 2,660	$ 5,500	$ 4,383	$ 7,682