SIGNIFICANT ACCOUNTING POLICIES - Additional Information (Details) - USD ($) $ in Millions	1 Months Ended	6 Months Ended
Aug. 31, 2021	Jun. 30, 2022	Jun. 30, 2021
SIGNIFICANT ACCOUNTING POLICIES
Receipt of product development research award	$ 13.1
Revenue from CPRIT		$ 1.8
The effect of adjustment in Net cash used in Operating and Investing activities			$ 1.0

The sum of adjustments which are added to or deducted from Net Cash Provided by (Used in) Operating activities and Net cash Provided by (Used in) Investing activities.

No definition available.

Name:	mrkr_AdjustmentsToNetCashProvidedByUsedInOperatingActivitiesAndInvestingActivities
Namespace Prefix:	mrkr_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration