Consolidated Balance Sheets (Parentheticals) - USD ($) |
Mar. 31, 2017 |
Dec. 31, 2016 |
|---|---|---|
| Current assets: | ||
| Allowance for doubtful accounts | $ 4,369,312 | $ 3,018,995 |
| Customer relationships and other intangible assets, accumulated amortization | $ 46,165,412 | $ 42,590,238 |
| Stockholders' equity: | ||
| Common stock, par value (in usd per share) | $ 0.0001 | $ 0.0001 |
| Common stock, shares authorized (in shares) | 100,000,000 | 100,000,000 |
| Common stock, shares issued (in shares) | 30,569,404 | 30,421,273 |
| Common stock, shares outstanding (in shares) | 28,242,515 | 28,131,479 |
| Treasury stock, shares (in shares) | 2,326,889 | 2,289,794 |