CONSOLIDATED STATEMENTS OF CASH FLOWS - USD ($) $ in Thousands	3 Months Ended		6 Months Ended		12 Months Ended
	Jun. 30, 2021	Jun. 30, 2020	Jun. 30, 2021	Jun. 30, 2020	Dec. 31, 2020
Cash flows from operating activities:
Net income (loss)	$ (14,641)	$ 1,655	$ (18,769)	$ 5,607	$ 19,808
Adjustments to reconcile net income (loss) to net cash used in operating activities:
Depreciation and amortization	2,480	2,601	4,850	4,489	9,150
Asset write-downs and impairment of field equipment	178	133	354	139	429
Share-based compensation	27,881	18,770	46,744	35,327	75,721
Foreign currency remeasurement loss (gain)	372	(463)	2,529	(470)	(699)
Decrease (increase) in accounts receivables	3,026	(6,160)	7,649	(25,878)	(30,354)
Amortization of discount (premium)	925	(538)	1,528	(1,078)	3,260
Decrease (increase) in inventories	1,663	(3,539)	367	(2,391)	(2,935)
Decrease (increase) in other long-term assets	1,584	1,143	3,016	2,379	(1,366)
Increase (decrease) in accounts payables and accrued expenses	5,122	405	2,496	(1,934)	25,470
Increase (decrease) in other long-term liabilities	(2,418)	(1,266)	(6,812)	(1,492)	664
Net cash provided by (used in) operating activities	26,172	12,741	43,952	14,698	99,148
Cash flows from investing activities:
Purchase of property, equipment and field equipment	(2,618)	(3,315)	(6,599)	(6,427)	(14,968)
Proceeds from maturity of short-term investments	0	0	608,000	0	150,000
Purchase of short-term investments	0	0	(549,848)	0	(607,879)
Net cash provided by (used in) investing activities	(2,618)	(3,315)	51,553	(6,427)	(472,847)
Cash flows from financing activities:
Proceeds from issuance of shares, net	2,371	1,667	2,371	1,667	3,370
Proceeds from long term debt, net	0	0	0	0	558,439
Repayment of long-term loan	(7)	(7)	(13)	(15)	(150,028)
Exercise of options and warrants	8,695	3,685	16,656	8,196	28,428
Net cash provided by (used in) financing activities	11,059	5,345	19,014	9,848	440,209
Effect of exchange rate changes on cash, cash equivalents and restricted cash	(3)	109	(105)	50	247
Increase (decrease) in cash, cash equivalents and restricted cash	34,610	14,880	114,414	18,169	66,757
Cash, cash equivalents and restricted cash at the beginning of the period	325,977	182,705	246,173	179,416	179,416
Cash, cash equivalents and restricted cash at the end of the period	360,587	197,585	360,587	197,585	246,173
Cash paid during the period for:
Income taxes paid (refunded), net	2,490	4,728	85	6,937	(3,261)
Interest paid	1	3,415	2	6,831	8,686
Non-cash activities:
Right-of-use assets obtained in exchange for lease liabilities	$ 665	$ 1,391	$ 949	$ 2,174	$ 5,617