Consolidated Balance Sheets (Parentheticals) - USD ($) |
Jun. 30, 2016 |
Dec. 31, 2015 |
|---|---|---|
| Current assets: | ||
| Allowance for doubtful accounts | $ 1,536,287 | $ 1,627,315 |
| Customer relationships and other intangible assets, accumulated amortization | $ 34,759,406 | $ 26,785,810 |
| Stockholders' equity: | ||
| Common stock, par value (in usd per share) | $ 0.0001 | $ 0.0001 |
| Common stock, shares authorized | 100,000,000 | 100,000,000 |
| Common stock, shares issued | 30,218,653 | 29,765,525 |
| Common stock, shares outstanding | 28,651,997 | 29,727,588 |
| Treasury stock, shares | 1,566,656 | 37,937 |