CONSOLIDATED STATEMENTS OF CASH FLOWS (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Cash Flows from Operating Activities:
Net income (loss)	$ (13,901)	$ (9,668)	$ 10,385
Adjustments to reconcile net income (loss) to net cash (used in) provided by operating activities:
Depreciation	134	131	131
Provision to reduce inventory to net realizable value	250	0	0
Share-based compensation	1,215	1,733	2,458
Gain on sales of marketable securities	(4)	0	0
Loss on asset disposals	0	8	8
Changes in assets and liabilities
Accounts receivable, net	(194)	0	0
Collaboration revenue receivable	0	0	126
Accrued investment income	(84)	0	0
Inventories	(282)	(219)	0
Income taxes refundable	43	110	(141)
Prepaid expenses and other current assets	(358)	(16)	(33)
Other current deferred assets	(186)	0	0
Other assets	6	0	0
Accounts payable	(720)	941	53
Accrued expenses	128	(64)	(209)
Deferred program fee revenue	0	0	(466)
Deferred revenue	287	0	0
Other liabilities	(12)	6	0
Net cash (used in) provided by operating activities	(13,678)	(7,038)	12,312
Cash Flows from Investing Activities:
Purchases of marketable securities	(7,611)	(20,306)	0
Proceeds from sale and maturities of marketable securities	13,887	320	0
Additions to property, plant and equipment	(23)	(147)	(131)
Net cash provided by (used in) investing activities	6,253	(20,133)	(131)
Cash Flows from Financing Activities:
Proceeds from exercise of stock options	9	9	217
Proceeds from distribution of restricted stock units	1	1	5
Statutory minimum withholding taxes paid on the distribution of common stock pursuant to restricted stock unit plan and exercise of stock options	(716)	(1,048)	(1,839)
Proceeds from warrant exercise	0	0	1,076
Long-term debt borrowings	10,000	0	0
Capitalized debt issuance costs	(231)	0	0
Proceeds from ''at the market offering''	3,328	0	0
“At the market offering” transaction costs	(102)	0	0
Net cash provided by (used) in financing activities	12,289	(1,038)	(541)
Net increase (decrease) in cash and cash equivalents	4,864	(28,209)	11,640
Cash and cash equivalents at beginning of year	7,476	35,685	24,045
Cash and cash equivalents at end of year	12,340	7,476	35,685
Cash paid (refunded) during the year for:
Interest	0	0	26
Income taxes, net of refunds	$ (42)	$ (108)	$ 284