CONSOLIDATED BALANCE SHEETS - USD ($) $ in Thousands	Jun. 30, 2017	Dec. 31, 2016
Current assets:
Cash and cash equivalents	$ 111,209	$ 153,225
Accounts receivable	4,877	2,129
Inventory	1,520	1,316
Prepaid expenses and other current assets	3,009	1,905
Total current assets	120,615	158,575
Property and equipment, net	1,583	1,038
Intangible assets, net	1,925	2,103
Restricted cash	97	97
Other long-term assets	295	204
Total assets	124,515	162,017
Current liabilities:
Accounts payable	5,612	9,106
Accrued expenses	10,199	8,879
Deferred revenue	10,361	4,944
Current portion of term loan payable	2,389	2,667
Total current liabilities	28,561	25,596
Lease incentive obligation	17	34
Term loan payable, long-term	424	1,479
Total liabilities	29,002	27,109
Commitments and contingencies (see Note 10)
Shareholders' equity:
Preferred stock, $0.001 par value; authorized shares - 5,000,000 at June 30, 2017 and December 31, 2016; issued and outstanding shares - none at June 30, 2017 and December 31, 2016
Common stock, $0.001 par value; authorized shares - 100,000,000 at June 30, 2017 and December 31, 2016; issued and outstanding shares - 29,565,411 at June 30, 2017 and 29,364,100 at December 31, 2016	30	29
Additional paid-in capital	362,866	358,063
Accumulated deficit	(267,383)	(223,184)
Total shareholders’ equity	95,513	134,908
Total liabilities and shareholders’ equity	$ 124,515	$ 162,017