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Economic conditional incentive grants.

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Percentage of fund to be withdrawn upon signing of arrangements.

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Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

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Notes Payable and Other Liabilities - Additional Information (Detail)			12 Months Ended
	Apr. 13, 2020 USD ($)	Jun. 05, 2019 EUR (€)	Dec. 31, 2020 USD ($)	Dec. 31, 2019 USD ($) FundingArrangement Grant	Dec. 31, 2019 EUR (€) FundingArrangement Grant	Dec. 31, 2019 EUR (€)
Debt Instrument [Line Items]
Revenues			$ 8,185,027	$ 5,801,401
Repayments of notes payable			632,000	292,002
Economic conditional incentive grants			250,000	250,000
Interest expense			9,421	$ 2,244
Montgomery County [Member]
Debt Instrument [Line Items]
Expiration date of economic conditional incentive grant				Feb. 28, 2028	Feb. 28, 2028
State of Maryland [Member]
Debt Instrument [Line Items]
Expiration date of economic conditional incentive grant				Dec. 31, 2029	Dec. 31, 2029
Economic incentive grant term				10 years	10 years
Montgomery County and State of Maryland [Member]
Debt Instrument [Line Items]
Economic conditional incentive grants				$ 250,000
Number of economic conditional incentive grants \| Grant				2	2
Interest expense			$ 12,625	$ 5,042
Accrued interest rate on grant			3.00%	3.00%	3.00%
Paycheck Protection Program Loan [Member]
Debt Instrument [Line Items]
Proceeds from unsecured loan	$ 632,000
Maturity date			Apr. 07, 2022
Interest rate			1.00%
BPI France Notes [Member]
Debt Instrument [Line Items]
Number of non-interest bearing research and development funding arrangements \| FundingArrangement				2	2
Percentage of fund to be withdrawn upon signing of arrangements				50.00%	50.00%
Additional percentage of fund to be withdrawn, contingent upon financial audit and technical progress report				30.00%	30.00%
Research and development funding arrangements extended period				2 years	2 years
Total long-term debt \| €						€ 500,000
Revenues				$ 265,540	€ 238,229
Paid in excess of allowable funding amount \| €		€ 102,951
Repayments of notes payable				292,002
BPI France Notes [Member] \| Research Funding First Arrangement [Member]
Debt Instrument [Line Items]
Debt instrument, face amount \| €						750,000
BPI France Notes [Member] \| Research Funding Second Arrangement [Member]
Debt Instrument [Line Items]
Debt instrument, face amount \| €						€ 250,000
BPI France Notes [Member] \| Grant [Member]
Debt Instrument [Line Items]
Long-term debt converted amount				$ 265,540	€ 238,229