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| 0001564590-17-023005-index.html | 2017-11-09 08:21:09 | |
| 0001564590-17-023005.txt | 2017-11-09 08:21:09 | |
 0001564590-17-023005-xbrl.zip | 97880 | 2017-11-09 08:21:09 |
| atra-10q_20170930.htm | 1759765 | 2017-11-09 08:21:09 |
| atra-20170930.xml | 1186043 | 2017-11-09 08:21:09 |
| atra-20170930.xsd | 34538 | 2017-11-09 08:21:09 |
| atra-20170930_cal.xml | 35581 | 2017-11-09 08:21:09 |
| atra-20170930_def.xml | 108946 | 2017-11-09 08:21:09 |
| atra-20170930_lab.xml | 302929 | 2017-11-09 08:21:09 |
| atra-20170930_pre.xml | 218880 | 2017-11-09 08:21:09 |
| atra-ex311_11.htm | 14993 | 2017-11-09 08:21:09 |
| atra-ex312_9.htm | 15113 | 2017-11-09 08:21:09 |
| atra-ex321_7.htm | 7732 | 2017-11-09 08:21:09 |
| FilingSummary.xml | 22734 | 2017-11-09 08:21:09 |
| Financial_Report.xlsx | 44319 | 2017-11-09 08:21:09 |
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| report.css | 2767 | 2017-11-09 08:21:09 |
| Show.js | 1410 | 2017-11-09 08:21:09 |