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Equity-Based Compensation - Narrative (Details) - USD ($)		1 Months Ended		3 Months Ended		6 Months Ended		12 Months Ended
	Jan. 01, 2022	May 31, 2021	Sep. 30, 2017	Jun. 30, 2022	Jun. 30, 2021	Jun. 30, 2022	Jun. 30, 2021	Dec. 31, 2020	Apr. 01, 2022	Mar. 24, 2022	Dec. 31, 2021	Sep. 22, 2017
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Granted (in shares)						232,028
Compensation cost not yet recognized				$ 2,850,000		$ 2,850,000
Compensation expense recognition period						3 years 1 month 6 days
Weighted-average grant date fair value (in dollars per share)						$ 2.52	$ 39.30
Aggregate intrinsic value, stock options, exercised						$ 0	$ 77,000
Stock option, exercise price (in dollars per share)									$ 5.51
Options outstanding (in shares)				317,262		317,262				233,224	331,420
Share-based compensation expense				$ 507,000	$ 764,000	$ 849,000	$ 1,281,000
Chief Financial Officer
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Granted (in shares)		20,000
Chief Financial Officer \| Elias Papadimas
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Options outstanding (in shares)										12,513
Chief Executive Officer \| Matthias Schroff
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Options outstanding (in shares)										29,373
Board of Directors \| Jeffrey Cleland
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Options outstanding (in shares)										3,835
Board of Directors \| Elizabeth Garofalo
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Options outstanding (in shares)										5,000
Board of Directors \| Bali Muralidhar
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Options outstanding (in shares)										3,835
Board of Directors \| James Sulat
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Options outstanding (in shares)										3,112
Employee Stock
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of shares available for grant (in shares)				42,471		42,471
Maximum ESPP contribution rate as a percentage of compensation			15.00%
Maximum number of shares per employee in purchase period (in shares)			250
Maximum contribution amount			$ 25,000
ESPP purchase price as a percentage of market price			85.00%
Offering period duration			6 months
Number of additional shares allowable annually under the plan (in shares)			10,000
Percentage of outstanding shares allowable as annual increase			0.30%
Increase in number of shares available for grant (in shares)	10,000
Restricted stock units
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting period						4 years
Number of shares issued for each vested restricted stock unit (in shares)				1		1
Performance Based Restricted Stock \| Period One
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting percentage						33.333%
Performance Based Restricted Stock \| Period Two
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting percentage						33.333%
Performance Based Restricted Stock \| Period Three
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting percentage						33.333%
Exicure, Inc. 2017 Equity Incentive Plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of shares authorized (in shares)												194,750
Number of shares available for grant (in shares)				139,679		139,679						72,330
Number of additional shares authorized, potential maximum additional shares (in shares)								153,333
Number of additional shares authorized, percentage of common stock outstanding								5.00%
Exicure, Inc. 2017 Equity Incentive Plan \| Options to purchase common stock
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of shares available for grant (in shares)	153,333
Expiration period						10 years
Exicure, Inc. 2017 Equity Incentive Plan \| Initial Employee Stock Option
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Monthly vesting percentage						2.08%
Vesting period						48 months
Exicure, Inc. 2017 Equity Incentive Plan \| Initial Employee Stock Option \| Non-employee Director
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Monthly vesting percentage						2.78%
Vesting period						36 months
Exicure, Inc. 2017 Equity Incentive Plan \| Initial Employee Stock Option \| Period One
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting percentage						25.00%
Exicure, Inc. 2017 Equity Incentive Plan \| Subsequent Employee Stock Option
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Monthly vesting percentage						2.08%
Vesting period						48 months
Exicure, Inc. 2017 Equity Incentive Plan \| Subsequent Employee Stock Option \| Non-employee Director
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Monthly vesting percentage						8.33%
Vesting period						12 months
Exicure OpCo 2015 Equity Incentive Plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of shares available for grant (in shares)												122,793
Equity Incentive Plans, Option Repricing \| Options to purchase common stock
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Compensation cost not yet recognized				$ 98,000		$ 98,000
Stock-based compensation incremental				291,000
Share-based compensation expense				$ 193,000