Consolidated Statements of Cash Flows - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2016	Mar. 31, 2015
Cash flows from operating activities
Net income	$ 4,825	$ 738
Adjustments to reconcile net income to net cash (used in) provided by operating activities:
Loss on extinguishment of debt	382	2,134
Change in fair value of derivative liability	(101)	49
Depreciation and amortization	429	214
Non cash interest expense, net/interest income, net	155	463
Non-recourse liability related to sale of future royalties	1,279	759
Non-cash royalty revenue	(1,119)	(605)
Share-based compensation expense	1,359	902
Changes in operating assets and liabilities:
Accounts receivable	(4,744)	(2,001)
Inventories	(457)	(261)
Prepaid expenses and other assets	260	38
Accounts payable	(1,691)	(1,004)
Accrued sales deduction	1,903	1,505
Accrued expenses	(5,995)	(1,883)
Deferred licensing revenue	300	(36)
Other non-current liabilities	73	(1,277)
Net cash (used in) provided by operating activities	(3,142)	(265)
Cash flows from investing activities
Purchases of marketable securities	(17,335)	(17,967)
Sales and maturities of marketable securities	7,400	8,731
Purchases of property and equipment	(279)	(189)
Deferred legal fees	(436)	(1,695)
Net cash used in investing activities	(10,650)	(11,120)
Cash flows from financing activities
Proceeds from issuance of common stock	124	147
Net cash provided by financing activities	124	147
Net change in cash and cash equivalents	(13,668)	(11,238)
Cash and cash equivalents at beginning of period	33,498	36,396
Cash and cash equivalents at end of period	19,830	25,158
Noncash financial activity:
Conversion of convertible notes and interest make-whole	2,138	21,176
Deferred legal fees included in accounts payable and accrued expenses	$ 3,779	$ 3,176