|
Commitments and Contingencies (Details) (USD $)
|
6 Months Ended | |
|---|---|---|
|
Jun. 30, 2012
|
Jun. 30, 2011
|
|
| Movement in Standard and Extended Product Warranty, Increase (Decrease) [Roll Forward] | ||
| Beginning balance - January 1 | $ 1,210,919 | $ 862,480 |
| Additions for current year deliveries | 346,970 | 445,570 |
| Reductions for payments made | (537,879) | (336,950) |
| Ending balance - June 30 | $ 1,020,010 | $ 971,100 |