Annual report pursuant to Section 13 and 15(d)

Consolidated Balance Sheets (Parentheticals)

v2.4.1.9
Consolidated Balance Sheets (Parentheticals) (USD $)
Dec. 31, 2014
Dec. 31, 2013
Preferred stock, par value (in dollars per share) $ 0.001us-gaap_PreferredStockParOrStatedValuePerShare $ 0.001us-gaap_PreferredStockParOrStatedValuePerShare
Preferred stock, shares authorized (in shares) 5,000,000us-gaap_PreferredStockSharesAuthorized 5,000,000us-gaap_PreferredStockSharesAuthorized
Common stock, par value (in dollars per share) $ 0.001us-gaap_CommonStockParOrStatedValuePerShare $ 0.001us-gaap_CommonStockParOrStatedValuePerShare
Common stock, shares authorized (in shares) 50,000,000us-gaap_CommonStockSharesAuthorized 50,000,000us-gaap_CommonStockSharesAuthorized
Common stock, shares issued (in shares) 12,891,317us-gaap_CommonStockSharesIssued 11,359,769us-gaap_CommonStockSharesIssued
Treasury stock, shares (in shares) 384,220us-gaap_TreasuryStockShares 26,998us-gaap_TreasuryStockShares
Series A Convertible Preferred Stock [Member]    
Preferred stock, shares authorized (in shares)   1,761,900us-gaap_PreferredStockSharesAuthorized
/ us-gaap_StatementClassOfStockAxis
= nhtc_SeriesAConvertiblePreferredStockMember
Preferred stock, shares issued (in shares)   123,693us-gaap_PreferredStockSharesIssued
/ us-gaap_StatementClassOfStockAxis
= nhtc_SeriesAConvertiblePreferredStockMember
Preferred stock, shares outstanding (in shares)   123,693us-gaap_PreferredStockSharesOutstanding
/ us-gaap_StatementClassOfStockAxis
= nhtc_SeriesAConvertiblePreferredStockMember