STATEMENTS OF CASH FLOWS - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Cash flows from operating activities:
Net income (loss)	$ 129,122	$ 8,140	$ (6,408)
Adjustments to reconcile net income (loss) to net cash provided by operations:
Stock-based compensation	13,361	7,058	6,013
Accretion of interest expense	456	1,929	2,848
Amortization of debt financing costs	14	21	22
Deferred taxes	(76,703)	0	0
Excess tax benefits from stock option activity	293	0	0
Depreciation and amortization of property and equipment	106	87	155
Changes in operating assets and liabilities:
Trade receivables	(5,440)	(3,639)	(2,887)
Other receivable (Note 11)	(12,896)	0	0
Inventory	(2,262)	(682)	815
Prepaid expenses and other current assets	(705)	(1,322)	799
Other assets	(26)	0	(7)
Accounts payable	6,289	965	(561)
Accrued clinical expenses	780	296	835
Other accrued liabilities	8,546	5,696	1,381
Deferred revenue	0	(158)	125
Net cash provided by operating activities	60,935	18,391	3,130
Cash flows from investing activities:
Purchases of property and equipment	(419)	(194)	(17)
Purchases of marketable securities	(73,037)	0	0
Cash used in investing activities	(73,456)	(194)	(17)
Cash flows from financing activities:
Proceeds from exercise of warrants, net of issuance costs	0	0	17,088
Proceeds from exercise of stock options, net of issuance costs	7,181	7,683	5,193
Payments related to debt obligation	(15,134)	(14,779)	(9,207)
Net cash (used in) provided by financing activities	(7,953)	(7,096)	13,074
Net (decrease) increase in cash and cash equivalents	(20,474)	11,101	16,187
Cash and cash equivalents, at beginning of period	51,536	40,435	24,248
Cash and cash equivalents, at end of period	31,062	51,536	40,435
Supplemental disclosure:
Income taxes paid	$ 377	$ 40	$ 57