CONDENSED CONSOLIDATED BALANCE SHEETS - USD ($) $ in Thousands	Jun. 30, 2017	Dec. 31, 2016	[1]
Current assets
Cash	$ 66,086	$ 77,329
Accounts receivable, net of allowance for doubtful accounts of $180 and $436 at June 30, 2017 and December 31, 2016, respectively	8,750	10,451
Prepaid expenses	6,950	2,579
Other current assets	7,571	21,014
Total current assets	89,357	111,373
Textbook library, net	0	2,575
Property and equipment, net	40,294	35,305
Goodwill	116,239	116,239
Intangible assets, net	17,970	20,748
Other assets	4,297	4,412
Total assets	268,157	290,652
Current liabilities
Accounts payable	809	5,175
Deferred revenue	12,457	14,836
Accrued liabilities	27,861	44,319
Total current liabilities	41,127	64,330
Long-term liabilities
Total other long-term liabilities	4,974	4,383
Total liabilities	46,101	68,713
Commitments and contingencies (Note 6)
Stockholders' equity:
Preferred stock, $0.001 par value – 10,000,000 shares authorized, no shares issued and outstanding	0	0
Common stock, $0.001 par value 400,000,000 shares authorized; 95,684,945 and 91,708,839 shares issued and outstanding at June 30, 2017 and December 31, 2016, respectively	96	92
Additional paid-in capital	605,638	593,351
Accumulated other comprehensive income (loss)	76	(176)
Accumulated deficit	(383,754)	(371,328)
Total stockholders' equity	222,056	221,939
Total liabilities and stockholders' equity	$ 268,157	$ 290,652

[1] Derived from audited consolidated financial statements as of and for the year ended December 31, 2016.