| Dec'19 | Dec'18 | Dec'17 | Dec'16 | Dec'15 | ||
|---|---|---|---|---|---|---|
Cash flows from operating activities: | ||||||
Net loss | ||||||
-248,497 | -210,752 | -131,325 | -80,824 | -35,816 | ||
Adjustments to reconcile net loss to net cash used in operating activities | ||||||
Depreciation expense | ||||||
4,100 | 1,600 | 1,000 | 534 | 115 | ||
Stock-based compensation expense | ||||||
32,929 | 32,732 | 16,719 | 12,641 | 6,157 | ||
Non-cash interest expense | ||||||
4,626 | - | - | - | - | ||
Amortization of premium on investment securities | ||||||
1,631 | 886 | -511 | -919 | -324 | ||
Changes in operating assets and liabilities: | ||||||
Prepaid expenses and other assets | ||||||
-3,888 | 1,995 | 1,435 | -3,967 | 9,698 | ||
Accounts payable | ||||||
6,200 | 2,688 | 2,315 | -994 | 1,072 | ||
Accrued liabilities | ||||||
2,039 | 7,412 | 11,557 | 6,803 | 1,859 | ||
Other liabilities | ||||||
952 | 75 | 1,087 | 340 | 297 | ||
Net cash used in operating activities | ||||||
-195,400 | -169,128 | -99,605 | -56,614 | -35,690 | ||
Purchase of property and equipment | ||||||
8,047 | 9,420 | 6,425 | 7,665 | 1,708 | ||
Purchase of investments | ||||||
166,321 | 261,293 | 129,534 | 197,178 | 152,811 | ||
Maturities of investments | ||||||
286,267 | 174,703 | 178,521 | 160,947 | 29,250 | ||
Net cash provided by (used in) investing activities | ||||||
111,899 | -96,010 | 42,562 | -43,896 | -125,229 | ||
Cash flows from financing activities: | ||||||
Borrowings under debt agreement | ||||||
40,000 | - | - | - | - | ||
Debt issuance costs | ||||||
3,856 | - | - | - | - | ||
Change in restricted cash | ||||||
- | - | - | - | -40 | ||
Proceeds from underwritten public offering, net of offering costs | ||||||
- | 288,435 | 6,520 | 145,000 | 168,119 | ||
Net cash proceeds from exercise of stock options | ||||||
20,406 | 10,727 | - | 2,843 | 303 | ||
Tax withholdings related to net share settlements of restricted stock units | ||||||
672 | - | - | - | - | ||
Net cash provided by financing activities | ||||||
55,878 | 299,162 | 6,520 | 147,843 | 235,327 | ||
Net increase (decrease) in cash and cash equivalents | ||||||
-27,631 | 34,024 | -50,523 | 47,333 | 74,408 | ||
Supplemental disclosure of non-cash investing and financing activities: | ||||||
Property and equipment purchases included in accounts payable and accrued liabilities | ||||||
1,048 | 1,301 | 1,355 | 558 | - | ||
Capital expenditures and interest funded through long term lease obligation | ||||||
- | - | - | - | 710 | ||
Supplemental cash flow disclosures: | ||||||
Cash paid for taxes | ||||||
- | 148 | 39 | - | - | ||