| | | December 31, | | ||||||
| | Estimated Useful Lives | | 2012 | | 2013 | | |||
Laboratory equipment | | | 7 | | $ | 3,748,201 | | $ | 4,796,393 | |
Office equipment and software | | | 3 7 | | | 809,146 | | | 972,789 | |
Leasehold improvements | | | 7 | | | 216,917 | | | 348,901 | |
Assets not in service | | | | | | 526,495 | | | 503,208 | |
| | | | | | 5,300,759 | | | 6,621,291 | |
Less accumulated depreciation | | | | | | (2,133,854) | | | (2,781,865) | |
| | | | | $ | 3,166,905 | | $ | 3,839,426 | |