2.Significant Balance Sheet Components

Accounts Receivable, Net —Accounts receivable, net at March 31, 2020 and December 31, 2019 consisted of the following (in thousands):


	March 31, 2020		December 31, 2019
Accounts receivable - billed	$	35,940	$	57,184
Accounts receivable - unbilled		2,166		2,043
Allowance for doubtful accounts		(412)		(412)
Accounts receivable, net	$	37,694	$	58,815

Property and Equipment —Property and equipment at March 31, 2020 and December 31, 2019 consisted of the following (in thousands):


	March 31, 2020		December 31, 2019
Computers and appliances	$	13,426	$	13,300
Purchased software		4,235		4,235
Furniture and fixtures		1,745		1,745
Leasehold improvements		3,403		3,403
Total property and equipment		22,809		22,683
Accumulated depreciation and amortization		(18,743)		(17,879)
Total property and equipment—net	$	4,066	$	4,804

Prepaid Expenses and Other Current Assets and Other Assets

Prepaid expenses and other current assets at March 31, 2020 and December 31, 2019 included $6.7 million and $6.3 million of prepaid royalties, respectively. Other assets at March 31, 2020 and December 31, 2019 included $2.3 million and $3.0 million of prepaid royalties, respectively. The prepaid royalties were primarily associated with MobileIron Threat Defense.

Accrued Expenses —Accrued expenses at March 31, 2020 and December 31, 2019 consisted of the following (in thousands):


	March 31, 2020		December 31, 2019
Accrued commissions	$	2,703	$	4,810
Accrued stock-settled bonus		—		6,875
Employee Stock Purchase Plan liability		873		2,187
Other accrued payroll-related expenses		2,849		2,839
Accrued royalties		3,080		2,386
Other accrued liabilities		5,576		5,695
Total accrued expenses	$	15,081	$	24,792