| Share-based Payment Arrangement, Option, Activity [Table Text Block] |
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Outstanding Stock Options | | | | | | | | Options Available for Grant | | Number of Options Outstanding | | Weighted
Average
Exercise Price
per Option | | Weighted
Average Grant
Date Fair Value
per Option | | Weighted
Average
Remaining
Exercise Term
in Months | | Balance, December 31, 2017 | 4,145,774 | | | 3,851,371 | | | $ | 3.11 | | | $ | 1.84 | | | 43 | | Granted | (340,000) | | | 340,000 | | | 1.18 | | | 0.54 | | | 56 | | Exercised | — | | | (52,500) | | | 1.24 | | | 0.68 | | | — | | | Forfeited | — | | | — | | | — | | | — | | | — | | | Expired | — | | | (271,250) | | | 3.22 | | | 1.58 | | | — | | | Balance, December 31, 2018 | 3,805,774 | | | 3,867,621 | | | 4.05 | | | $ | 1.84 | | | 64 | | Additional Shares Authorized under 2019 Plan | 8,000,000 | | | — | | | | | | | | | Granted | (2,400,000) | | | 2,400,000 | | | 0.96 | | | 0.53 | | | 81 | | Exercised | — | | | (498,552) | | | 0.13 | | | 1.92 | | | | | Forfeited | 1,375,069 | | | (1,375,069) | | | 4.75 | | | 1.95 | | | 27 | | Expired | — | | | — | | | | | | | | | Balance, June 30, 2019 | 10,780,843 | | | 4,394,000 | | | $ | 2.60 | | | $ | 1.32 | | | 94 |
|