Consolidated Balance Sheets (Parentheticals) - USD ($)
|
Dec. 31, 2018 |
Dec. 31, 2017 |
| Common Stock, par value (in dollars per share) |
$ 0.01
|
$ 0.01
|
| Common Stock, shares authorized |
750,000,000
|
750,000,000
|
| Common Stock, shares issued |
234,160,661
|
229,073,517
|
| Common stock in treasury, shares |
15,002,663
|
587,151
|
| Series C Redeemable Convertible Preferred Stock |
|
|
| Redeemable convertible Preferred Stock, par value (in dollars per share) |
$ 0.01
|
$ 0.01
|
| Redeemable convertible Preferred Stock, shares authorized |
10,431
|
10,431
|
| Redeemable convertible Preferred Stock, shares issued |
2,620
|
2,620
|
| Redeemable convertible Preferred Stock, shares outstanding |
2,620
|
2,620
|
| Redeemable convertible Preferred Stock, aggregate involuntary liquidation preference (in dollars) |
$ 16,664,000
|
$ 16,664,000
|
| Series E Redeemable Convertible Preferred Stock |
|
|
| Redeemable convertible Preferred Stock, par value (in dollars per share) |
$ 0.01
|
$ 0.01
|
| Redeemable convertible Preferred Stock, shares authorized |
35,000
|
0
|
| Redeemable convertible Preferred Stock, shares issued |
35,000
|
0
|
| Redeemable convertible Preferred Stock, shares outstanding |
35,000
|
0
|
| Redeemable convertible Preferred Stock, aggregate involuntary liquidation preference (in dollars) |
$ 35,000,000
|
$ 0
|