Consolidated Statements of Cash Flows (Unaudited) - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017
Cash flows from operating activities:
Net loss	$ (104,293)	$ (100,672)
Adjustments to reconcile net loss to net cash used in operating activities:
Depreciation and amortization	2,771	2,475
Increase in fair value of Symphony Icon, Inc. purchase liability	0	2,101
Stock-based compensation	8,849	7,214
Amortization of debt issuance costs	957	412
Deferred tax benefit	0	(8,652)
Loss on disposal of property and equipment	0	(2)
Changes in operating assets and liabilities:
(Increase) decrease in accounts receivable	1,912	(3,105)
Increase in inventory	(2,807)	(2,149)
(Increase) decrease in prepaid expenses and other current assets	1,039	(580)
Decrease in other assets	0	32
Decrease in accounts payable and other liabilities	(4,700)	(11,738)
Decrease in deferred revenue	(25,207)	(37,023)
Net cash used in operating activities	(121,479)	(151,683)
Cash flows from investing activities:
Purchases of property and equipment	(58)	(224)
Purchases of investments	(84,475)	(59,237)
Maturities of investments	195,358	245,749
Net cash provided by investing activities	110,825	186,288
Cash flows from financing activities:
Proceeds from issuance of common stock	550	5,481
Repurchase of common stock	(972)	(1,679)
Proceeds from debt borrowings, net of fees	12,529	0
Repayment of debt borrowings, net of fees	(14,212)	(1,714)
Net cash (used in) provided by financing activities	(2,105)	2,088
Net increase (decrease) in cash and cash equivalents	(12,759)	36,693
Cash and cash equivalents at beginning of period	61,661	46,600
Cash and cash equivalents at end of period	48,902	83,293
Supplemental disclosure of cash flow information:
Cash paid for interest	10,470	3,272
Supplemental disclosure of non-cash investing and financing activities:
Common stock issued in satisfaction of Symphony Icon payment obligation	0	10,499
Unrealized gain on investments	$ 151	$ 132