Note 5 - Fair Value of Financial Instruments - Assets Measured on Recurring Basis (Details) - USD ($)
|
Jun. 30, 2019 |
Mar. 31, 2019 |
| Total |
$ 61,611,878
|
$ 74,117,263
|
| Money Market Funds [Member] |
|
|
| Total |
12,774,255
|
6,703,809
|
| Corporate Bond Securities [Member] |
|
|
| Total |
61,611,878
|
67,413,454
|
| Fair Value, Recurring [Member] |
|
|
| Total |
74,386,133
|
74,117,263
|
| Fair Value, Recurring [Member] | Money Market Funds [Member] |
|
|
| Total |
12,774,255
|
6,703,809
|
| Fair Value, Recurring [Member] | Corporate Bond Securities [Member] |
|
|
| Total |
61,611,878
|
67,413,454
|
| Fair Value, Recurring [Member] | Fair Value, Inputs, Level 1 [Member] |
|
|
| Total |
12,774,255
|
6,703,809
|
| Fair Value, Recurring [Member] | Fair Value, Inputs, Level 1 [Member] | Money Market Funds [Member] |
|
|
| Total |
12,774,255
|
6,703,809
|
| Fair Value, Recurring [Member] | Fair Value, Inputs, Level 1 [Member] | Corporate Bond Securities [Member] |
|
|
| Total |
|
|
| Fair Value, Recurring [Member] | Fair Value, Inputs, Level 2 [Member] |
|
|
| Total |
61,611,878
|
67,413,454
|
| Fair Value, Recurring [Member] | Fair Value, Inputs, Level 2 [Member] | Money Market Funds [Member] |
|
|
| Total |
|
|
| Fair Value, Recurring [Member] | Fair Value, Inputs, Level 2 [Member] | Corporate Bond Securities [Member] |
|
|
| Total |
$ 61,611,878
|
$ 67,413,454
|