Consolidated Statements of Cash Flows - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Cash flows from operating activities:
Net income (loss)	$ 19,808	$ (7,230)	$ (63,559)
Adjustments to reconcile net income (loss) to net cash provided by (used in) operating activities:
Depreciation and amortization	9,150	8,460	9,006
Asset write-downs and impairment of field equipment	429	398	407
Share-based compensation	75,721	52,416	39,846
Foreign currency remeasurement loss (gain)	(699)	(917)	0
Decrease (increase) in accounts receivables	(30,354)	(36,496)	(10,325)
Amortization of discount (premium)	3,260	(2,176)	1,022
Decrease (increase) in inventories	(2,935)	(1,159)	(529)
Decrease (increase) in other long-term assets	(1,366)	3,446	(949)
Increase (decrease) in accounts payables and accrued expenses	25,470	16,883	13,713
Increase (decrease) in other long-term liabilities	664	(7,006)	9,503
Net cash provided by (used in) operating activities	99,148	26,620	(1,865)
Cash flows from investing activities:
Purchase of property, equipment and field equipment	(14,968)	(10,485)	(6,711)
Proceeds from maturity of short-term investments	150,000	420,661	255,000
Purchase of short-term investments	(607,879)	(461,843)	(253,782)
Net cash provided by (used in) investing activities	(472,847)	(51,667)	(5,493)
Cash flows from financing activities:
Proceeds from issuance of shares, net	3,370	2,467	1,835
Proceeds from long-term debt, net	558,439	0	149,150
Repayment of long-term debt	(150,028)	(31)	(100,084)
Exercise of options and warrants	28,428	59,245	18,468
Net cash provided by (used in) financing activities	440,209	61,681	69,369
Effect of exchange rate changes on cash, cash equivalents and restricted cash	247	26	27
Increase (decrease) in cash, cash equivalents and restricted cash	66,757	36,660	62,038
Cash, cash equivalents and restricted cash at the beginning of the year	179,416	142,756	80,718
Cash, cash equivalents and restricted cash at the end of the year	246,173	179,416	142,756
Cash paid during the year for:
Income taxes paid (refunded), net	(3,261)	11,241	20,350
Interest	8,686	13,699	13,334
Non-cash activities:
Right-of-use assets obtained in exchange for lease liabilities	$ 5,617	$ 22,943	$ 0