Note 3 - Short Term Investments Available for Sale - Short-term Investment by Bond Maturities (Details) - USD ($) |
Dec. 31, 2016 |
Dec. 31, 2015 |
|---|---|---|
| Short-term investments, fair value | $ 10,799,890 | |
| Total short-term investments | $ 1,680,000 | 10,803,748 |
| Total short-term investments | 1,680,000 | 10,799,890 |
| Certificate of Deposit [Member] | ||
| Short-term investments, cost | 1,680,000 | 4,800,000 |
| Short-term investments, fair value | 1,680,000 | 4,798,810 |
| Investment Maturing Within Three Months [Member] | ||
| Total short-term investments | 1,680,000 | 10,803,748 |
| Total short-term investments | 1,680,000 | 10,799,890 |
| Corporate Debt Securities [Member] | ||
| Short-term investments, cost | 6,003,748 | |
| Short-term investments, fair value | 6,001,080 | |
| Investment Maturing Between 3 and 12 Months [Member] | ||
| Total short-term investments | ||
| Total short-term investments |