Condensed Balance Sheets - USD ($)
$ in Thousands |
Jun. 30, 2016 |
Dec. 31, 2015 |
Dec. 31, 2014 |
| Current assets: |
|
|
|
| Cash and cash equivalents |
$ 3,832
|
$ 5,117
|
$ 8,496
|
| Restricted cash |
50
|
50
|
50
|
| Short-term investments |
2,000
|
5,500
|
|
| Prepaid expenses |
477
|
311
|
442
|
| Total current assets |
6,359
|
10,978
|
8,988
|
| Property and equipment, net |
135
|
163
|
183
|
| Other assets |
27
|
18
|
18
|
| Total assets |
6,521
|
11,159
|
9,189
|
| Current liabilities: |
|
|
|
| Accounts payable |
297
|
1,163
|
285
|
| Accrued expenses |
1,256
|
1,106
|
1,002
|
| Deferred revenue |
|
|
47
|
| Total current liabilities |
1,553
|
2,269
|
1,334
|
| Commitments and contingencies |
|
|
|
| Stockholders' equity: |
|
|
|
| Preferred stock |
|
0
|
0
|
| Common stock |
1
|
1
|
|
| Additional paid-in capital |
66,515
|
65,994
|
48,049
|
| Accumulated deficit |
(61,548)
|
(57,105)
|
(46,882)
|
| Total stockholders' equity |
4,968
|
8,890
|
2,745
|
| Total liabilities, convertible preferred stock and stockholders' equity |
$ 6,521
|
$ 11,159
|
9,189
|
| Series A Convertible Preferred Stock [Member] |
|
|
|
| Convertible preferred stock: |
|
|
|
| Series A convertible preferred stock, $0.0001 par value, no shares authorized, issued or outstanding at December 31, 2015; 15,000 shares authorized and 5,110 shares issued and outstanding at December 31, 2014 (at liquidation value) |
|
|
5,110
|
| Series A-1 Convertible Preferred Stock [Member] |
|
|
|
| Stockholders' equity: |
|
|
|
| Preferred stock |
|
|
1,578
|
| Total stockholders' equity |
|
|
$ 1,578
|