Condensed Consolidated Statements of Cash Flows - USD ($)	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Operating activities
Net loss	$ (73,339,000)	$ (39,385,000)	$ (63,358,000)
Adjustments to reconcile net loss to net cash provided by (used in) operating activities:
Depreciation	1,815,000	1,219,000	469,000
Amortization of intangible assets	20,183,000
Amortization of premium on marketable securities		1,065,000	1,904,000
Stock-based compensation	23,993,000	29,875,000	27,650,000
Noncash interest expense	20,381,000	7,127,000	99,000
Provision for inventory excess and obsolescence	2,451,000	1,548,000	225,000
Other non-cash losses		2,000
Excess tax expense (benefit) from stock-based compensation	62,000	(62,000)
Unrealized foreign exchange loss	(933,000)
Loss on disposal of property and equipment	66,000
Deferred income taxes	501,000
Deferred rent	(135,000)
Changes in assets and liabilities, excluding the effect of acquisition:
Accounts receivable	3,568,000	(9,563,000)	(7,572,000)
Inventories	2,518,000	(10,170,000)	(1,594,000)
Prepaid expenses and other assets	(5,327,000)	173,000	(3,600,000)
Accounts payable	1,071,000	5,485,000	(1,116,000)
Accrued and other liabilities	19,106,000	10,635,000	8,406,000
Net cash provided by (used in) operating activities	15,981,000	(2,051,000)	(38,487,000)
Investing activities
Purchases of property and equipment	(1,879,000)	(3,940,000)	(716,000)
Payment for acquisition of MYALEPT	(325,000,000)
Purchases of marketable securities		(46,494,000)	(77,910,000)
Maturities of marketable securities		64,522,000	53,632,000
Sales and redemptions of marketable securities		46,090,000	2,194,000
Net cash (used in) provided by investing activities	(326,879,000)	60,178,000	(22,800,000)
Financing activities
Proceeds from long-term debt, net	24,962,000
Increase in restricted cash to collateralize long-term debt in default	(25,529,000)
Change in restricted cash			105,000
Proceeds from issuances of convertible notes		325,000,000
Proceeds from issuances of warrants		60,547,000
Purchase of convertible bond hedges		(86,645,000)
Principal repayment of long-term debt	(4,010,000)	(3,578,000)	(3,022,000)
Repurchase of common stock		(35,000,000)	10,038,000
Payments for withholding taxes on restricted stock units	(369,000)
Proceeds from exercises of stock options	4,255,000	3,738,000
Payment of financing fees		(8,450,000)
Excess tax expense (benefit) from stock-based compensation	(62,000)	62,000
Proceeds from issuances of common stock, net of offering expenses			78,020,000
Net cash (used in) provided by financing activities	(753,000)	255,674,000	85,141,000
Exchange rate effect on cash	215,000	1,125,000	(14,000)
Net (decrease) increase in cash and cash equivalents	(311,436,000)	314,926,000	23,840,000
Cash and cash equivalents, beginning of period	375,937,000	61,011,000	37,171,000
Cash and cash equivalents, end of period	64,501,000	375,937,000	61,011,000
Supplemental disclosures of cash flow information
Cash paid for interest	7,204,000	402,000	638,000
Cash paid for taxes	1,319,000	1,089,000	115,000
Non-cash investing activities
Purchases of property and equipment included in accounts payable	$ 184,000	$ 122,000	$ 263,000