CONSOLIDATED STATEMENTS OF CASH FLOWS - USD ($) $ in Thousands	6 Months Ended
	Jun. 30, 2020	Jun. 30, 2019
Cash flows from operating activities
Net loss	$ (70,550)	$ (59,171)
Adjustments to reconcile net loss to net cash used in operating activities:
Depreciation and amortization	3,505	3,217
Share-based compensation expense	10,078	8,886
Change in fair value of derivative financial instruments	(2,206)	2,634
Unrealized foreign exchange gains	(908)	(386)
Changes in operating assets and liabilities:
Accounts receivable and accrued income, prepaid expenses and other current assets	1,050	(2,779)
Accounts payable	(981)	283
Accrued expenses, other liabilities and operating leases	(1,332)	(658)
Deferred revenue	(1,600)	(2,683)
Net cash used in operating activities	(62,944)	(50,657)
Cash flows from investing activities
Purchases of intangible assets	(2,214)	(996)
Purchases of property, plant and equipment	(2,392)	(1,432)
Net cash used in investing activities	(4,606)	(2,428)
Cash flows from financing activities
Proceeds from issuance of shares related to employee stock option and purchase plans	3,549	2,721
Proceeds from exercise of warrants		500
Net cash generated from financing activities	3,549	3,221
Currency effect on cash, cash equivalents and restricted cash	223	(443)
Net decrease in cash, cash equivalents and restricted cash	(63,778)	(50,307)
Cash, cash equivalents and restricted cash at beginning of period	380,726	237,342
Cash, cash equivalents and restricted cash at the end of period	316,948	187,035
Total cash, cash equivalents and restricted cash	316,948	187,035
Supplemental cash flow disclosures:
Cash paid for interest	(2,545)	(1,544)
Non-cash increases in accounts payables and accrued expenses and other current liabilities related to purchases of intangible assets and property, plant and equipment	$ 1,021	$ 473