Inventories - Charges Associated With the Valuation of Inventory (Details) - USD ($) $ in Thousands	12 Months Ended
Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Inventory Disclosure [Abstract]
Inventory, net	$ 15,050	$ 6,120	$ 1,447
Adverse purchase commitments(A)	2,913	(1,908)	1,831
Net charges (B)	$ 17,963	$ 4,212	$ 3,278

Inventory Charges, Inventory Valuation, Deposit And Adverse Purchase Commitment Liability

No definition available.

Name:	rsys_InventoryChargesInventoryValuationDepositAndAdversePurchaseCommitmentLiability
Namespace Prefix:	rsys_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration