Commitments and Contingencies - Additional Information (Details) $ in Millions	3 Months Ended
Mar. 31, 2019 USD ($)
Commitments And Contingencies [Line Items]
Percentage of maximum borrowing capacity of value of eligible securities	70.00%
Available line of credit	$ 96.7
Available interest rate on line of credit	4.00%
Minimum [Member]
Commitments And Contingencies [Line Items]
Warranty period	12 months
Maximum [Member]
Commitments And Contingencies [Line Items]
Warranty period	15 months

Commitments and contingencies line items.

No definition available.

Name:	rtec_CommitmentsAndContingenciesLineItems
Namespace Prefix:	rtec_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- Definition

Maximum borrowing capacity percentage of eligible securities held at line of credit accessed.

+ References

No definition available.

+ Details

Name:	rtec_MaximumBorrowingCapacityPercentageOfEligibleSecuritiesHeldAtLineOfCreditAccessed
Namespace Prefix:	rtec_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration

- Definition

Product warranty accrual warranty period.

+ References

No definition available.

+ Details

Name:	rtec_ProductWarrantyAccrualWarrantyPeriod
Namespace Prefix:	rtec_
Data Type:	xbrli:durationItemType
Balance Type:	na
Period Type:	duration

- Definition

The effective interest rate at the end of the reporting period.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02.19(b),22(b))
-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

+ Details

Name:	us-gaap_LineOfCreditFacilityInterestRateAtPeriodEnd
Namespace Prefix:	us-gaap_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	instant

- Definition

Amount of borrowing capacity currently available under the credit facility (current borrowing capacity less the amount of borrowings outstanding).

+ References

+ Details

Name:	us-gaap_LineOfCreditFacilityRemainingBorrowingCapacity
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Details

Name:	srt_RangeAxis=srt_MinimumMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	srt_RangeAxis=srt_MaximumMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type: