CONSOLIDATED STATEMENTS OF CASH FLOWS - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Operating Activities
Net income (loss)	$ 15,566	$ (34,382)	$ (24,753)
Adjustments to reconcile net income (loss) to net cash provided by operating activities:
Depreciation and amortization expense	13,845	10,451	6,072
Amortization of debt discount and issuance costs	1,727	10,096	0
Provision for expected credit losses	2,333	3,016	2,322
Provision (recovery) for inventory obsolescence	467	(57)	2,353
Change in fair value of common stock warrants	1,386	17,087	11,075
Amortization of premium (discount) on short-term investments	365	(1,296)	(565)
Benefit for deferred income taxes	0	(2,126)	(25)
Stock-based compensation expense	60,752	58,431	58,071
Other	546	38	(295)
Changes in operating assets and liabilities:
Accounts receivable, net	(30,980)	(38,837)	(13,698)
Inventories	(4,954)	(15,361)	(30,975)
Prepaid and other current assets	(1,570)	(2,427)	(584)
Other long-term assets	1,313	129	(580)
Accounts payable	10,275	1,118	8,910
Accrued expenses	4,640	(3,256)	4,076
Employee-related liabilities	17,399	5,339	4,285
Deferred revenue	10,611	7,029	4,589
Operating leases and other current liabilities	6,217	5,789	4,216
Other long-term liabilities	1,421	3,888	7,412
Net cash provided by operating activities	111,359	24,669	41,906
Investing Activities
Purchases of short-term investments	(733,388)	(497,076)	(164,572)
Proceeds from maturities of short-term investments	545,735	180,922	114,908
Proceeds from sales of short-term investments	24,288	52,392	12,250
Purchases of property and equipment	(14,180)	(27,408)	(19,541)
Acquisition of intangible assets and equity investments	(9,331)	(4,886)	0
Net cash used in investing activities	(186,876)	(296,056)	(56,955)
Financing Activities
Proceeds from issuance of convertible senior notes, net of $8,809 debt issuance costs	0	278,691	0
Payment for capped call transactions related to convertible senior notes	0	(34,069)	0
Proceeds from issuance of common stock under Company stock plans, net	51,340	66,866	23,880
Proceeds from exercise of common stock warrants	592	2,950	327
Net cash provided by financing activities	51,932	314,438	24,207
Effect of foreign exchange rate changes on cash	153	387	191
Net increase (decrease) in cash and cash equivalents	(23,432)	43,438	9,349
Cash and cash equivalents at beginning of period	94,613	51,175	41,826
Cash and cash equivalents at end of period	71,181	94,613	51,175
Supplemental disclosures of cash flow information
Interest paid	4,313	2,707	0
Income taxes paid	260	177	67
Supplemental schedule of non-cash investing and financing activities
Right-of-use assets obtained in exchange for operating lease obligations	15,191	11,022	11,635
Property and equipment included in accounts payable	1,034	1,082	2,134
Intangible costs in accounts payable and other long-term liabilities	$ 1,029	$ 2,244	$ 0