Consolidated Balance Sheets - USD ($) $ in Thousands	Mar. 31, 2018	Sep. 30, 2017
Current assets:
Cash and cash equivalents	$ 66,926	$ 65,675
Short-term marketable securities	189,797	157,994
Accounts receivable	44,049	10,614
Prepaid expenses and other current assets	4,905	3,536
Total current assets	305,677	237,819
Long-term marketable securities	32,186	70,038
Property and equipment, net	8,616	8,049
Deferred tax assets	7,567	10,123
Restricted cash	608	608
Total assets	354,654	326,637
Current liabilities:
Accounts payable	4,696	3,714
Accrued expenses and other current liabilities	7,041	7,970
Income taxes payable	5,380	9,298
Total current liabilities	17,117	20,982
Warrant liability		807
Series 1 nonconvertible preferred stock	1,528	762
Other long-term liabilities	2,607	2,410
Total liabilities	21,252	24,961
Commitments and contingencies (Note 11)
Stockholders' equity:
Common stock; $0.01 par value per share, 100,000 shares authorized; 19,260 and 19,120 shares issued and outstanding at March 31, 2018 and September 30, 2017, respectively	193	191
Additional paid-in capital	264,354	256,241
Accumulated other comprehensive loss	(794)	(112)
Retained earnings	69,649	45,356
Total stockholders' equity	333,402	301,676
Total liabilities and stockholders' equity	$ 354,654	$ 326,637