STOCK-BASED COMPENSATION - Schedule of Stock-based Compensation (Details) - USD ($) $ in Thousands	3 Months Ended
Mar. 31, 2021	Mar. 31, 2020
Allocation of stock-based compensation expense
Stock compensation expense	$ 2,147	$ 1,379
Research and development
Allocation of stock-based compensation expense
Stock compensation expense	972	648
Sales, marketing and administration
Allocation of stock-based compensation expense
Stock compensation expense	$ 1,175	$ 731

Amount of cost expensed and capitalized for award under share-based payment arrangement.

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 718
-SubTopic 10
-Section 50
-Paragraph 2
-Subparagraph (h)(1)
-URI http://asc.fasb.org/extlink&oid=120381028&loc=d3e5070-113901

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Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration