Condensed Consolidated Balance Sheets (USD $) In Thousands, unless otherwise specified	Jun. 30, 2014	Dec. 31, 2013
Current assets:
Cash and cash equivalents	$ 76,861	$ 61,291
Certificates of deposit	249	249
Prepaid expenses	446	773
State research and development credit receivable	497	329
Other receivables	161	1,328
Total current assets	78,214	63,970
Leasehold improvements and equipment:
Leasehold improvements	5,577	5,588
Computer equipment	1,261	1,133
Lab equipment	3,994	3,724
Total leasehold improvements and equipment	10,832	10,445
Less accumulated depreciation and amortization	(4,376)	(3,858)
Leasehold improvements and equipment, net	6,456	6,587
Total assets	84,670	70,557
Current liabilities:
Accounts payable	687	612
Accrued expenses	2,891	2,861
Accrued Income Taxes, Current	5	130
Deferred rent	84	84
Current portion of long term debt	190	189
Total current liabilities	3,857	3,876
Long term liabilities:
Royalty obligation payable to Iowa Economic Development Authority	6,000	6,000
Notes payable and obligations under capital leases	937	1,033
Deferred rent, excluding current portion	1,279	1,321
Total long-term liabilities	8,216	8,354
Total liabilities	12,073	12,230
Equity (deficit):
Blank check preferred stock, $0.01 par value: Authorized shares — 5,000,000 at June 30, 2014 and December 31, 2013; issued and outstanding shares — 0 at June 30, 2014 and December 31, 2013	0	0
Common stock, $0.01 par value: Authorized shares — 75,000,000 at June 30, 2014 and December 31, 2013; issued shares — 27,912,198 and outstanding shares — 27,903,705 at June 30, 2014, and issued and outstanding shares — 26,573,023 at December 31, 2013	279	266
Additional paid-in capital	226,876	194,038
Treasury stock	(182)	0
Retained deficit	(154,376)	(135,977)
Total equity	72,597	58,327
Total liabilities and equity	$ 84,670	$ 70,557