Quarterly report pursuant to Section 13 or 15(d)

Note 4 - Stockholders' Equity - Stock Options by Exercise Price Range (Details)

v3.19.2
Note 4 - Stockholders' Equity - Stock Options by Exercise Price Range (Details) - USD ($)
6 Months Ended 12 Months Ended
Jun. 30, 2019
Dec. 31, 2018
Number of options outstanding (in shares) 125,481  
Weighted- average exercise price (in dollars per share) $ 136.85 $ 215.60
Weighted- average remaining contractual life (Year) 6 years 182 days 5 years 36 days
Aggregate intrinsic value  
Range One [Member]    
Range of exercise prices, lower limit (in dollars per share) $ 6.80  
Range of exercise prices, upper limit (in dollars per share) $ 10  
Number of options outstanding (in shares) 46,379  
Weighted- average exercise price (in dollars per share) $ 8.20  
Weighted- average remaining contractual life (Year) 9 years 182 days  
Aggregate intrinsic value  
Range Two [Member]    
Range of exercise prices, lower limit (in dollars per share) $ 20  
Range of exercise prices, upper limit (in dollars per share) $ 70  
Number of options outstanding (in shares) 29,432  
Weighted- average exercise price (in dollars per share) $ 23  
Weighted- average remaining contractual life (Year) 6 years 292 days  
Aggregate intrinsic value  
Range Three [Member]    
Range of exercise prices, lower limit (in dollars per share) $ 70.20  
Range of exercise prices, upper limit (in dollars per share) $ 260  
Number of options outstanding (in shares) 26,612  
Weighted- average exercise price (in dollars per share) $ 195.20  
Weighted- average remaining contractual life (Year) 3 years 292 days  
Aggregate intrinsic value  
Range Four [Member]    
Range of exercise prices, lower limit (in dollars per share) $ 260.20  
Range of exercise prices, upper limit (in dollars per share) $ 520  
Number of options outstanding (in shares) 14,937  
Weighted- average exercise price (in dollars per share) $ 299  
Weighted- average remaining contractual life (Year) 3 years  
Aggregate intrinsic value  
Range Five [Member]    
Range of exercise prices, lower limit (in dollars per share) $ 520.20  
Range of exercise prices, upper limit (in dollars per share) $ 1,120  
Number of options outstanding (in shares) 8,121  
Weighted- average exercise price (in dollars per share) $ 793  
Weighted- average remaining contractual life (Year) 3 years 146 days  
Aggregate intrinsic value