Consolidated Statements of Cash Flows - USD ($)
$ in Thousands |
12 Months Ended |
Dec. 31, 2015 |
Dec. 31, 2014 |
Dec. 31, 2013 |
| Cash flows from operating activities |
|
|
|
| Net loss |
$ (89,782)
|
$ (47,492)
|
$ (24,838)
|
| Adjustments to reconcile net loss to net cash used in operating activities: |
|
|
|
| Depreciation and amortization |
5,321
|
2,315
|
928
|
| Stock-based compensation |
3,477
|
971
|
260
|
| Amortization of premium on marketable securities |
632
|
|
|
| Loss on disposal of assets |
23
|
37
|
|
| Changes in operating assets and liabilities |
|
|
|
| Prepaid expenses and other current assets |
(1,676)
|
(1,880)
|
(363)
|
| Other assets |
36
|
(849)
|
(4)
|
| Accounts payable |
508
|
2,072
|
220
|
| Accrued expenses and other liabilities |
806
|
2,386
|
767
|
| Net cash used in operating activities |
(80,655)
|
(42,440)
|
(23,030)
|
| Cash flows from investing activities |
|
|
|
| Purchase of marketable securities |
(216,994)
|
|
|
| Proceeds from sales and maturities of marketable securities |
162,567
|
|
|
| Purchases of property and equipment |
(6,464)
|
(6,686)
|
(4,520)
|
| Change in restricted cash |
(4,681)
|
(30)
|
(60)
|
| Net cash used in investing activities |
(65,572)
|
(6,716)
|
(4,580)
|
| Cash flows from financing activities |
|
|
|
| Proceeds from issuance of convertible preferred stock, net of issuance costs |
|
115,731
|
49,819
|
| Proceeds from issuance of common stock upon initial public offering, net of issuance costs |
107,120
|
|
|
| Proceeds from exercise of stock options |
288
|
209
|
67
|
| Proceeds from loan agreement, net of financing costs |
7,453
|
|
|
| Loan payments |
(413)
|
|
|
| Capital lease principal payment |
(2,010)
|
(1,376)
|
(1,007)
|
| Payments for deferred offering costs |
|
(1,451)
|
|
| Net cash provided by financing activities |
112,438
|
113,113
|
48,879
|
| Net increase (decrease) in cash and cash equivalents |
(33,789)
|
63,957
|
21,269
|
| Cash and cash equivalents at beginning of period |
107,027
|
43,070
|
21,801
|
| Cash and cash equivalents at end of period |
73,238
|
107,027
|
43,070
|
| Supplemental cash flow information |
|
|
|
| Interest paid |
211
|
61
|
56
|
| Supplemental cash flow information of non-cash investing and financing activities: |
|
|
|
| Equipment acquired through capital leases |
1,639
|
2,850
|
1,793
|
| Conversion of preferred stock into common stock upon initial public offering costs |
202,305
|
|
|
| Change in purchases of property and equipment in accounts payable and accrued liabilities |
$ 603
|
325
|
$ 49
|
| Deferred offering costs included in accounts payable and accrued liabilities |
|
$ 450
|
|