Income Taxes - Schedule of Effective Income Tax Rate Reconciliation (Parenthetical) (Details) $ in Millions	12 Months Ended
Dec. 31, 2017 USD ($)
Income Taxes [Abstract]
Change in valuation allowance for deferred tax assets related to Tax Act	$ 1.5

Tax Cuts And Jobs Act of 2017 related to change in valuation allowance for deferred tax assets.

No definition available.

Name:	rtec_TaxCutsAndJobsActOf2017RelatedToChangeInValuationAllowanceForDeferredTaxAssets
Namespace Prefix:	rtec_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration