Consolidated Statements of Cash Flows - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017
Cash flows from operating activities
Net loss	$ (13,342)	$ (15,223)
Adjustments to reconcile net loss to net cash used in operating activities:
Non-cash other expense, net	(112)	(266)
Non-cash interest income	(10)	(30)
Depreciation and amortization expense	133	76
Stock-based compensation	1,244	684
Deferred income taxes		178
Other, net	(6)	86
Changes in operating assets and liabilities:
Changes in long-term receivables	(3)	(5)
Changes in other receivables and prepaid expense	(1,992)	(1,586)
Changes in accounts payable	(1,413)	1,789
Changes in accrued expenses and other liabilities	(1,311)	(383)
Changes in other non-current liabilities	22	6
Changes in income tax liabilities	451	(10)
Net cash used in operating activities	(16,339)	(14,684)
Cash flows from investing activities
Purchases of plant and equipment and intangible assets	(160)	(25)
Proceeds from sales of property, plant and equipment		2
Proceeds from sales of available-for-sale securities		10,000
Net cash provided by (used in) investing activities	(160)	9,977
Cash flows from financing activities
Proceeds from sale of ordinary shares	19,388
Proceeds from long-term debt	189	229
Proceeds from exercise of stock options		10
Equity transaction costs	(518)	(1,410)
Net cash provided by (used in) financing activities	19,059	(1,171)
Effects of foreign currency translation on cash and cash equivalents	112	266
Net (decrease) increase in cash and cash equivalents	2,672	(5,612)
Cash and cash equivalents at beginning of period	86,769	32,778
Cash and cash equivalents at end of period	$ 89,441	$ 27,166