Condensed Consolidated Statements of Cash Flows - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018
Operating activities:
Net loss	$ (72,421)	$ (23,418)
Adjustments to reconcile net loss to net cash used in operating activities:
Depreciation and amortization	439	199
Amortization of intangibles	9,100
Amortization of premium/discount on investments	(477)	(60)
Non-cash interest expense	169
Non-cash operating lease expense	(614)
Fair value write-up of inventory sold	14,586
Write-down of inventory to net realizable value	1,664	0
Stock-based compensation	2,094	2,232
Deferred income taxes	(2,757)
Changes in operating assets and liabilities:
Accounts receivable	(31,769)	(1,636)
Inventory	(16,064)
Prepaid expenses and other current assets	1,317	(1,496)
Other long-term assets	719
Accounts payable	(20,746)	10,882
Accrued expense	(17,500)	2,399
Operating lease liabilities	549
Deferred revenue	(6,218)	(9,391)
Deferred rent		(41)
Net cash used in operating activities	(137,929)	(20,330)
Investing activities:
Purchase of equipment	(1,928)	(296)
Proceeds from the maturities of available for sale securities	78,691	56,330
Proceeds from sales of available for sale securities	33,710	4,999
Purchase of available for sale securities		(48,599)
Net cash provided by investing activities	110,473	12,434
Financing activities:
Proceeds from the issuance of common stock, net of issuance costs		95,511
Proceeds from the sale of stock under employee stock purchase plan	188	218
Proceeds from the exercise of stock options	365	183
Payments on debt	(15,000)
Payments on capital lease obligations		(1)
Net cash provided by (used in) financing activities	(14,447)	95,911
Increase (decrease) in cash, cash equivalents, and restricted cash	(41,903)	88,015
Cash, cash equivalents, and restricted cash at beginning of the period	107,099	71,437
Cash, cash equivalents, and restricted cash at end of the period	$ 65,196	159,452
Non-cash financing activities
Unpaid follow-on offering costs		$ 95