In millions, except per share items | Sep-30-17 | Jun-30-17 | Mar-31-17 | Dec-31-16 | Sep-30-16 | Jun-30-16 | Mar-31-16 | Dec-31-15 |
| 10-Q | 10-Q | 10-Q | 10-K | 10-Q | 10-Q | 10-Q | 10-K |
Assets | | | | | | | | |
Current assets: | | | | | | | | |
Cash and cash equivalents | 14.5 | 25.1 | 24.0 | 30.2 | 74.9 | 104.7 | 117.0 | 127.0 |
Marketable securities | 19.2 | 22.4 | 35.1 | 47.7 | 18.8 | | | |
Accounts receivable | 2.8 | 3.1 | 2.4 | 1.9 | 1.8 | 1.3 | 1.3 | 0.1 |
Prepaid expenses and other current assets | 6.6 | 6.1 | 8.6 | 5.5 | 2.9 | 3.7 | 2.6 | 2.7 |
Total current assets | 43.1 | 56.7 | 70.1 | 85.3 | 98.5 | 109.7 | 120.9 | 129.9 |
Property and equipment, net | 6.8 | 7.3 | 7.9 | 8.4 | 8.7 | 7.9 | 6.2 | 3.3 |
Deferred offering costs | 0.2 | 0.2 | 0.2 | 0.1 | | | | |
Total assets | 50.1 | 64.2 | 78.2 | 93.9 | 107.2 | 117.6 | 127.2 | 133.3 |
|
Liabilities and Stockholders’ Equity | | | | | | | | |
Current liabilities: | | | | | | | | |
Accounts payable | 1.0 | 1.3 | 1.4 | 2.4 | 1.4 | 0.6 | 2.2 | 1.6 |
Accrued expenses and other current liabilities | 7.6 | 3.3 | 4.3 | 7.2 | 7.0 | 5.5 | 5.0 | 3.7 |
Deferred revenue | 10.5 | 9.9 | 9.2 | 8.7 | 7.8 | 7.4 | 7.1 | 6.8 |
Notes payable | 2.3 | 2.5 | 2.5 | 2.4 | 2.0 | 1.4 | 0.6 | 0.6 |
Total current liabilities | 21.4 | 17.0 | 17.4 | 20.6 | 18.1 | 14.8 | 15.0 | 13.2 |
Deferred revenue, net of current portion | 5.1 | 7.4 | 9.3 | 8.7 | 11.8 | 13.1 | 14.5 | 13.7 |
Notes payable, net of discount and current portion | 2.8 | 3.3 | 3.6 | 4.2 | 4.8 | 3.8 | 0.6 | 0.8 |
Other liabilities | 0.4 | 0.4 | 0.4 | 0.5 | 0.5 | 0.5 | 0.5 | 0.1 |
Total liabilities | 29.8 | 28.1 | 30.7 | 33.9 | 35.1 | 32.3 | 30.6 | 27.7 |
|
Commitments and contingencies (Note 9) | | | | | | | | |
Stockholders’ equity: | | | | | | | | |
Preferred stock, $0.0001 par value; 5,000,000 shares authorized at September 30, 2017 and December 31, 2016; zero shares issued or outstanding at September 30, 2017 and December 31, 2016. | | | | | | | | |
Common stock | 0.0 | 0.0 | 0.0 | 0.0 | 0.0 | 0.0 | 0.0 | 0.0 |
Additional paid-in capital | 163.3 | 162.1 | 161.2 | 160.2 | 159.2 | 158.1 | 157.3 | 156.8 |
Accumulated deficit | -142.9 | -126.0 | -113.7 | -100.2 | -87.2 | -72.8 | -60.7 | -51.2 |
Accumulated other comprehensive loss | 0.0 | -0.1 | -0.1 | -0.1 | 0.0 | | | |
Total stockholders’ equity | 20.3 | 36.1 | 47.5 | 59.9 | 72.0 | 85.3 | 96.6 | 105.6 |
Total liabilities and stockholders’ equity | 50.1 | 64.2 | 78.2 | 93.9 | 107.2 | 117.6 | 127.2 | 133.3 |