Aggregate number of common shares reserved for future issuance.

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 10
-Section S99
-Paragraph 1
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No definition available.

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Number of options outstanding, including both vested and non-vested options.

+ References

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

Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 718
-SubTopic 10
-Section 50
-Paragraph 2
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STOCKHOLDERS' EQUITY - EQUITY PLANS - SCHEDULE OF AGGREGATE STOCK OPTION AND AWARD ACTIVITY (Parenthetical) (Details) - shares	Feb. 28, 2022	Dec. 31, 2021	Dec. 31, 2020
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Stock options outstanding (in shares)		49,952,409	43,663,691
Common stock, shares reserved for future issuance (in shares)		133,292,810
2018 Inducement Award Plan
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Common stock, shares reserved for future issuance (in shares)		15,100,000
Performance-Based Stock Options
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Stock options outstanding (in shares)		6,050,000
Subsequent Event \| 2018 Inducement Award Plan
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Common stock, shares reserved for future issuance (in shares)	16,100,000