STOCK REPURCHASE PROGRAM (Details Narrative) (USD $)	12 Months Ended
STOCK REPURCHASE PROGRAM (Details Narrative) (USD $)	Dec. 31, 2014	Jun. 03, 2014	Aug. 22, 2011
Stock Repurchase Details Narrative
Additional dollar amount of Maximum shares for repurchase over the next 12 months (in dollars)		$ 5,000,000
Total dollor amount of shares for repurchase since inception of repurchase program			12,000,000
Shares repurchased	2,335,740nssi_SharesRepurchased
Shares repurchased-average price per share	$ 1.90
Dollar amount of stock repurchase	$ 4,439,484nssi_DollarAmountOfStockRepurchase
Shares repurchased since inception	5,749,068nssi_SharesRepurchasedSinceInception
Shares repurchased since inception - average price per share	$ 1.54
Dollar amount of shares repurchased since inception	$ 8,872,107