Subsequent Events	3 Months Ended
Mar. 31, 2018
Subsequent Events [Abstract]
Subsequent Events	NOTE 6 - Subsequent Events On April 6, 2018, Sigma issued 1,000 shares of the Company’s newly-created non-voting Series B Convertible Preferred Stock, which are initially convertible into 1,000,000 shares of common stock and warrants to purchase an aggregate of 750,000 shares of the Company’s common stock, for an aggregate purchase price of $1,000,000. The warrants have an initial exercise price of $1.47 per share, the closing price of the Company’s Common Stock reported on The NASDAQ Capital Market on April 6, 2018, subject to adjustment in certain circumstances. The net proceeds to the company were approximately $840,000 after commissions and other offering expenses. Sigma also issued Dawson James Securities, Inc., its placement agent in the foregoing private placement, warrants to purchase up to 140,000 shares of common stock, at an exercise price of $1.47 per share, as compensation. On April 19, 2018, Sigma granted John Rice, our interim Chief Executive Officer, three options to purchase up to 20,000 shares of our common stock under our 2013 Plan. On April 30, 2018, Sigma granted Mr. Rice an option to purchase up to 20,000 shares of our common stock under our 2013 Plan. The foregoing options have an exercise price per share equal to $1.88, $1.54, $1.48 and $1.2580 respectively, which is at least the closing price of our common stock on the respective date of grant, and each is fully vested as of the respective grant date. The Company also agreed to grant Mr. Rice an option to purchase up to 20,000 shares on each of May 31, 2018, June 30, 2018 and July 31, 2018 (each, a “Monthly Option”), so long as Mr. Rice remains an employee of the Company as of the applicable grant date (except that if Mr. Rice ceases to be employed by the Company as a result of a disability), any Monthly Option that has not been granted as of such date (i.e., prior to July 31, 2018) will still be granted on the applicable grant date), with an exercise price equal to the greater of (x) the average closing price of our common stock during the applicable month, and (y) the closing price of our common stock on the date of grant, and will be vested in full on the date of grant. On April 19, 2018, Sigma issued each of its four non-employee directors 44,186 shares of common stock, under the 2013 Equity Incentive Plan, with such shares to vest ratably over four quarterly installments, subject in each case to such director’s continuing service as a director. On April 19, 2018, Sigma granted Ron Fisher, our Vice President of Business Development, a five-year option to purchase an aggregate of 28,750 shares of common stock, with such option having an exercise price of $1.22 per share, and vesting in four annual installments over four years following the date of grant (1,366 shares, 4,097 shares, 6,828 shares and 15,021 shares, respectively).

Subsequent Events

3 Months Ended

Mar. 31, 2018

NOTE 6 - Subsequent Events

On April 6, 2018, Sigma issued 1,000 shares of the Company’s newly-created non-voting Series B Convertible Preferred Stock, which are initially convertible into 1,000,000 shares of common stock and warrants to purchase an aggregate of 750,000 shares of the Company’s common stock, for an aggregate purchase price of $1,000,000. The warrants have an initial exercise price of $1.47 per share, the closing price of the Company’s Common Stock reported on The NASDAQ Capital Market on April 6, 2018, subject to adjustment in certain circumstances. The net proceeds to the company were approximately $840,000 after commissions and other offering expenses. Sigma also issued Dawson James Securities, Inc., its placement agent in the foregoing private placement, warrants to purchase up to 140,000 shares of common stock, at an exercise price of $1.47 per share, as compensation.

On April 19, 2018, Sigma granted John Rice, our interim Chief Executive Officer, three options to purchase up to 20,000 shares of our common stock under our 2013 Plan. On April 30, 2018, Sigma granted Mr. Rice an option to purchase up to 20,000 shares of our common stock under our 2013 Plan. The foregoing options have an exercise price per share equal to $1.88, $1.54, $1.48 and $1.2580 respectively, which is at least the closing price of our common stock on the respective date of grant, and each is fully vested as of the respective grant date. The Company also agreed to grant Mr. Rice an option to purchase up to 20,000 shares on each of May 31, 2018, June 30, 2018 and July 31, 2018 (each, a “Monthly Option”), so long as Mr. Rice remains an employee of the Company as of the applicable grant date (except that if Mr. Rice ceases to be employed by the Company as a result of a disability), any Monthly Option that has not been granted as of such date (i.e., prior to July 31, 2018) will still be granted on the applicable grant date), with an exercise price equal to the greater of (x) the average closing price of our common stock during the applicable month, and (y) the closing price of our common stock on the date of grant, and will be vested in full on the date of grant.

On April 19, 2018, Sigma issued each of its four non-employee directors 44,186 shares of common stock, under the 2013 Equity Incentive Plan, with such shares to vest ratably over four quarterly installments, subject in each case to such director’s continuing service as a director.

On April 19, 2018, Sigma granted Ron Fisher, our Vice President of Business Development, a five-year option to purchase an aggregate of 28,750 shares of common stock, with such option having an exercise price of $1.22 per share, and vesting in four annual installments over four years following the date of grant (1,366 shares, 4,097 shares, 6,828 shares and 15,021 shares, respectively).