Condensed Consolidated Balance Sheets - USD ($) $ in Thousands	Sep. 30, 2016	Dec. 31, 2015
Current assets:
Cash and cash equivalents	$ 148,276	$ 195,620
Certificates of deposit	0	2,180
Prepaid expenses and other current assets	10,688	4,954
Income tax receivable	5,197	0
Other receivables	14,995	5,388
Total current assets	179,156	208,142
Property and equipment, net	7,188	10,400
Total assets	186,344	218,542
Current liabilities:
Accounts payable	2,367	3,661
Accrued expenses	37,259	8,761
Income taxes payable	0	859
Current portion of unearned revenue	693	892
Current portion of deferred rent	81	96
Current portion of notes payable and obligations under capital leases	245	571
Total current liabilities	40,645	14,840
Long-term liabilities:
Royalty obligation payable to Iowa Economic Development Authority	6,000	6,000
Notes payable and obligations under capital leases	333	368
Unearned revenue	0	407
Deferred rent	1,089	1,153
Total long-term liabilities	7,422	7,928
Total liabilities	48,067	22,768
Stockholders' equity:
Blank check preferred stock, $0.01 par value: Authorized shares — 5,000,000 at September 30, 2016 and December 31, 2015; issued and outstanding shares — 0 at September 30, 2016 and December 31, 2015	0	0
Common stock, $0.01 par value: Authorized shares — 75,000,000 at September 30, 2016 and December 31, 2015; issued 29,116,879 and 28,838,176 at September 30, 2016 and December 31, 2015, respectively, and outstanding 29,091,652 and 28,814,142 at September 30, 2016 and December 31, 2015, respectively	291	288
Additional paid-in capital	290,772	276,610
Treasury stock, at cost: 25,227 and 24,034 shares at September 30, 2016 and December 31, 2015, respectively	(784)	(771)
Accumulated deficit	(152,002)	(80,353)
Total stockholders' equity	138,277	195,774
Total liabilities and stockholders' equity	$ 186,344	$ 218,542