Condensed Consolidated Statements of Cash Flows - USD ($) $ in Thousands	6 Months Ended
	Jun. 30, 2021	Jun. 30, 2020
Statement of Cash Flows [Abstract]
Consolidated net income (loss)	$ 19,225	$ (12,013)
Adjustments to reconcile consolidated net income (loss) to net cash used in operating activities:
Depreciation and amortization	7,022	6,090
Stock-based compensation	16,198	11,248
Inventory write-downs	1,951	1,716
Deferred taxes	2,570	(5,240)
Other	1,309	2,629
Changes in operating assets and liabilities:
Accounts receivable	(22,898)	6,757
Inventories	(41,543)	(31,935)
Prepaid expenses and other current and non-current assets	(5,843)	(4,255)
Accounts payable	(689)	(6)
Accrued expenses and other non-current liabilities	5,020	(5,100)
Net cash provided by (used in) operating activities	(17,678)	(27,609)
CASH FLOWS FROM INVESTING ACTIVITIES:
Purchases of marketable investments	(32,939)	(60,320)
Proceeds from sales of marketable investments	2,000	7,188
Proceeds from maturities of marketable investments	67,810	27,535
Purchases of property and equipment	(7,286)	(16,850)
Impairment of intangible asset	0	2,500
Other	(150)	(2,060)
Net cash provided by (used in) investing activities	29,435	(44,507)
CASH FLOWS FROM FINANCING ACTIVITIES:
Proceeds from issuance of common stock upon underwritten public offering, net of issuance cost	0	134,759
Proceeds from exercises of stock options	978	1,187
Proceeds from issuance of stock under employee stock purchase plan	7,354	5,945
Payment of employee taxes related to vested stock	(6,988)	(3,873)
Payments of finance lease obligations	(692)	(2,976)
Payment of acquisition-related obligations	0	(683)
Other	(93)	(248)
Net cash provided by financing activities	559	134,111
Effect of foreign exchange rate changes on cash and cash equivalents	291	(393)
NET INCREASE IN CASH AND CASH EQUIVALENTS	12,607	61,602
CASH AND CASH EQUIVALENTS—Beginning of period	69,670	72,779
CASH AND CASH EQUIVALENTS—End of period	82,277	134,381
NONCASH INVESTING AND FINANCING ACTIVITIES:
Right-of-use assets obtained in exchange for lease obligations	54,444	830
Purchase of property and equipment funded through accounts payable and accrued liabilities	2,236	666
SUPPLEMENTAL CASH FLOW INFORMATION:
Cash paid for amounts included in the measurement of operating lease liabilities	$ 3,914	$ 3,740