Consolidated Statements of Cash Flows - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2016	Mar. 31, 2015
Cash flows from operating activities
Net loss	$ (15,034)	$ (14,257)
Adjustments to reconcile net loss to net cash used by operating activities:
Depreciation and amortization expense	734	548
Amortization of debt discount	1	9
Stock-based compensation expense	944	1,088
Provision for bad debts on trade receivables	0	42
Changes in operating assets and liabilities:
Accounts receivable	1,332	(714)
Inventories	(399)	(1,348)
Prepaid expenses and other assets	555	(1,557)
Accounts payable and accrued liabilities	694	2,581
Deferred royalty revenue	(76)	0
Other long-term liabilities	(20)	(49)
Net cash used in operating activities	(11,269)	(13,657)
Cash flows from investing activities:
Acquisition of property and equipment	(3,298)	(1,415)
Decrease (increase) in restricted cash	0	56
Purchase of short term investment	(26,939)	0
Net cash used in investing activities	(30,237)	(1,359)
Cash flows from financing activities:
Proceeds from exercise of common stock options	825	126
Payments on long-term debt	(72)	(68)
Net cash provided by financing activities	753	58
Foreign exchange effect on cash and cash equivalents	151	(3)
(Decrease) increase in cash and cash equivalents	(40,602)	(14,961)
Cash and cash equivalents, beginning of period	117,185	37,900
Cash and cash equivalents, end of period	76,583	22,939
Supplemental information:
Cash paid for income taxes	10	29
Cash paid for interest	$ 8	$ 242