Desktop Metal, Inc. General form of registration statement for all companies including face-amount certificate companies

STOCK BASED COMPENSATION - Stock Incentive Plan (Details)

v3.21.2

STOCK BASED COMPENSATION - Stock Incentive Plan (Details) $ in Millions	1 Months Ended		3 Months Ended		12 Months Ended
	Dec. 31, 2020 USD ($) shares	Jul. 31, 2020 USD ($) employee	Mar. 31, 2021 USD ($) shares	Mar. 31, 2020 USD ($) shares	Dec. 31, 2020 USD ($) shares	Dec. 31, 2019 USD ($) shares	Dec. 31, 2018 shares	Dec. 31, 2015 shares
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting period					1 year
Number of employees affected by repricing \| employee		116
Granted (in shares)					8,463,000
Expenses recognized \| $		$ 3.6
Unrecognized stock-based compensation expense, stock options \| $	$ 13.7		$ 12.5		$ 13.7	$ 13.0
Weighted-average period			3 years 1 month 6 days		2 years 9 months 18 days
Shares available for grant	14,379,052		14,140,956		14,379,052
Consultant
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Granted (in shares)				12,212	12,212	119,581
Fair value of shares \| $				$ 0.1	$ 0.1	$ 0.6
Employee
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Granted (in shares)			0	473,624	8,450,799	5,730,586
Fair value of shares \| $				$ 0.8	$ 29.8	$ 10.1
Share-based Payment Arrangement, Nonemployee [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Granted (in shares)			0
2015 stock incentive plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Awards made under the plan								26,283,789
Vesting period								4 years
Expiration period								10 years
Make Plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting period						4 years	4 years
Expiration period						10 years	10 years
Options and warrants to be issued						232,304	232,304
Granted (in shares)						0	0
2020 Plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Common stock available for future issuance	12,400,813				12,400,813
Percentage of stock outstanding	5.00%

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Number of employees affected by repricing.

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Period over which grantee's right to exercise award under share-based payment arrangement is no longer contingent on satisfaction of service or performance condition, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents reported fact of one year, five months, and thirteen days. Includes, but is not limited to, combination of market, performance or service condition.

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Gross number of share options (or share units) granted during the period.

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Maximum number of shares that may be issued in accordance with the plan as a proportion of outstanding capital stock.

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Period from grant date that an equity-based award expires, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.

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