XML 41 R32.htm IDEA: XBRL DOCUMENT v3.19.2

Significant Accounting Policies - Additional Information (Detail) € in Millions	6 Months Ended
	Jun. 30, 2019 EUR (€) Segment
Disclosure of significant accounting policies [abstract]
Number of reportable segment | Segment	1
Cash and cash equivalents, maximum original maturities	3 months
Short-term investments | €	€ 49.0

X

- Definition

A classification of cash equivalents representing short-term investments. [Refer: Cash equivalents]

+ References

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Name IAS
-Number 7
-IssueDate 2018-01-01
-Paragraph 45
-URI http://eifrs.ifrs.org/eifrs/XBRL?type=IAS&num=7&date=2018-03-01&anchor=para_45&doctype=Standard
-URIDate 2018-03-16

+ Details

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Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

X

- Definition

Cash And Cash Equivalents Maximum Maturity Period

+ References

No definition available.

+ Details

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Namespace Prefix:	mrus_
Data Type:	xbrli:durationItemType
Balance Type:	na
Period Type:	duration

X

- Definition

Disclosure of significant accounting policies.

+ References

No definition available.

+ Details

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Namespace Prefix:	mrus_
Data Type:	xbrli:stringItemType
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X

- Definition

Number of reportable segments.

+ References

No definition available.

+ Details

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Namespace Prefix:	mrus_
Data Type:	xbrli:integerItemType
Balance Type:	na
Period Type:	duration