Consolidated Statements of Cash Flows - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Cash flows from operating activities
Net loss	$ (114,780)	$ (74,356)	$ (54,890)
Adjustments to reconcile net loss to net cash used in operating activities:
Non-cash other income, net	362	(1,371)	996
Non-cash interest income	45		(52)
Non-cash interest expense	(104)		35
Depreciation and amortization expense	510	432	233
Stock-based compensation	5,154	5,732	2,545
In-process research and development	32,048
Deferred income taxes		1,410	(794)
Other, net	14	131	1
Changes in operating assets and liabilities:
Changes in long-term receivables	(3)	(5)	10
Changes in other receivables	1,139	(223)	(1,932)
Changes in accounts payable	(2,969)	2,585	(383)
Changes in accrued expenses and other liabilities	5,742	(3,778)	6,034
Changes in other non-current liabilities	61	96	24
Changes in income tax liabilities	58	(1)	(152)
Net cash used in operating activities	(72,723)	(69,348)	(48,325)
Cash flows from investing activities
Purchases of plant and equipment and intangible assets	(229)	(1,173)	(603)
Purchases of available-for-sale securities			(57,035)
Purchases of term deposits	(115)	(30)	(10)
Proceeds from sale of property, plant and equipment		2
Proceeds from maturities of term deposits			45,000
Proceeds from sales of available-for-sale securities		50,950	36,000
Transaction costs for Zavante acquisition, net of cash acquired	(4,260)
Net cash provided (used in) by investing activities	(4,604)	49,749	23,352
Cash flows from financing activities
Proceeds from December 2016 financing			24,822
Proceeds from long-term debt	25,535	228
Proceeds from exercise of stock options		83	269
Debt transaction costs	(1,990)
Equity transaction costs	(4,841)	(8,092)	(2,790)
Net cash provided by financing activities	92,923	72,219	22,301
Effects of foreign currency translation on cash and cash equivalents	(362)	1,371	(996)
Net increase (decrease) in cash and cash equivalents	15,234	53,991	(3,668)
Cash and cash equivalents at beginning of year	86,769	32,778	36,446
Cash and cash equivalents at end of year	102,003	86,769	32,778
Supplemental disclosures of cash flow information:
Interest paid	(7)	(1)	(41)
Taxes paid	(4)	(5)	(867)
Equity transaction costs included in accounts payable and accrued expenses	120	28	$ 1,451
September 2017 public offering
Cash flows from financing activities
Proceeds from issuance of stock		$ 80,000
July 2018 public offering
Cash flows from financing activities
Proceeds from issuance of stock	50,000
At-the-market offering
Cash flows from financing activities
Proceeds from issuance of stock	$ 24,219