Consolidated Statements of Cash Flows - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Cash flows from operating activities:
Net loss	$ (131,845)	$ (111,581)	$ (80,682)
Adjustments to reconcile net loss to net cash used in operating activities:
Depreciation and amortization	5,652	3,153	1,962
Asset write-downs and impairment of field equipment	6,446	46	23
Increase in accrued interest expense		672
Share-based compensation to employees	22,139	11,860	4,624
Excess tax benefits from share-based award activity	(698)
Increase in trade receivables	(6,339)
Amortization of discount (premium)	155	329	(19)
Decrease (increase) in receivables and prepaid expenses	243	(5,088)	(1,192)
Increase in inventories	(11,955)	(10,148)	(1,554)
Increase in other long-term assets	(692)	(381)	(44)
Increase (decrease) in trade payables	1,601	6,961	(492)
Increase in other payables and accrued expenses	6,647	3,579	2,324
Increase in employee benefit liabilities, net	97	133	42
Increase in other long-term liabilities	957	581	764
Net cash used in operating activities	(107,592)	(99,884)	(74,244)
Cash flows from investing activities:
Purchase of property and equipment	(5,674)	(4,667)	(849)
Purchase of field equipment	(11,990)	(5,604)	(1,470)
Decrease (increase) in restricted cash	(180)	(26)	1,117
Proceeds from maturity of short-term investments	270,000	104,000	93,000
Purchase of short-term investments	(239,341)	(208,998)	(137,980)
Net cash provided by (used in) investing activities	12,815	(115,295)	(46,182)
Cash flows from financing activities:
Proceeds from issuance of shares, net	616	252,133
Proceeds from long-term loan, net	72,887	22,886
Excess tax benefits from share-based award activity	698
Proceeds from issuance of other long-term loans			54
Repayment of other long-term loans	(70)	(63)	(63)
Exercise of options and warrants	993	2,038	2,154
Purchase of shares in respect of settlement		(5)
Net cash provided by financing activities	75,124	276,989	2,145
Effect of exchange rate changes on cash and cash equivalents	10
Increase (decrease) in cash and cash equivalents	(19,643)	61,810	(118,281)
Cash and cash equivalents at the beginning of the year	119,423	57,613	175,894
Cash and cash equivalents at the end of the year	99,780	119,423	57,613
Cash paid during the year for:
Income taxes	9,447	1,489	282
Interest	$ 6,595	$ 1,688	25
Non-cash investing and financing activities:
Purchase of property and equipment			$ 239