Disclosure of Compensation Related Costs, Share-based Payments [Text Block] | ( 7 ) Share-Based Compensation The share-based compensation expense is recorded in cost of goods sold, research and development, and selling, general and administrative expenses based on the employee's respective function. No three six June 30, 2018 2017 Three months ended June 30, Six months ended June 30, 2018 2017 2018 2017 Cost of goods sold $ 36 $ 33 $ 66 $ 74 Research and development 264 154 461 326 Selling, general and administrative 438 489 826 898 Share-based compensation expense $ 738 $ 676 $ 1,353 $ 1,298 The following table summarizes the activity of stock options and related information: Weighted average Number of exercise shares price Balance, December 31, 2017 4,213,100 $ 2.96 Stock options granted 1,603,075 2.48 Stock options exercised (2,488 ) 1.80 Stock options cancelled (135,487 ) 2.69 Balance, June 30, 2018 5,678,200 $ 2.83 The weighted average grant-date fair value of options granted during the six June 30, 2018 $1.77 Employee Share-Based Compensation (Stock Options) During the six June 30, 2018, 1,603,075 Risk-free interest rate 2.66% - 2.87% Volatility 81% Dividend yield None Expected term (in years) 6.25 Unrecognized share-based compensation for employee options as of June 30, 2018 $6.3 2.8 Restricted Stock Units (RSUs) The following summarizes the activity of non-vested RSUs: Weighted average grant date Number of fair value shares per share Balance, December 31, 2017 97,996 $ 8.71 RSUs vested (57,108 ) 7.03 Balance, June 30, 2018 40,888 $ 11.04 Unrecognized share-based compensation for employee RSUs granted as of June 30, 2018 $348,000 1.5 Nonemployee Share-Based Compensation During the six June 30, 2018, not $31,000 $277,000 three June 30, 2018 2017, $76,000 $510,000 six June 30, 2018 2017, We account for share-based compensation arrangements with nonemployees, using the Black-Scholes option pricing model, based on the fair value as these instruments vest. Accordingly, at each reporting date, we revalue the unearned portion of the share-based compensation and the resulting change in fair value is recognized in the consolidated statements of operations over the period the related services are rendered. The following assumptions were used to value the awards for the six June 30, 2018: Risk-free interest rate 2.80% - 2.84% Volatility 78% - 80% Dividend yield None Expected term (in years) 8.1 - 8.8 |