Significant Accounting Policies (Tables)

12 Months Ended

Dec. 31, 2018

Significant Accounting Policies [Abstract]

Schedule of cash, cash equivalents, and restricted cash

The following table illustrates the reconciliation of cash, cash equivalents, and restricted cash shown in the consolidated statements of cash flows as of December 31, 2017 and 2018 (in thousands):


	As of December 31,
	2017		2018
Cash and cash equivalents	$	155,933	$	311,732
Restricted cash included in other current assets		15		5
Restricted cash included in other long-term assets		500		500
Total cash, cash equivalents, and restricted cash shown in the statement of cash flows	$	156,448	$	312,237

Schedule of tuition receivable and allowance for doubtful accounts

The Company’s tuition receivable and allowance for doubtful accounts were as follows as of December 31, 2017 and 2018 (in thousands):


	December 31, 2017		December 31, 2018
Tuition receivable	$	35,809	$	84,151
Allowance for doubtful accounts		(12,687)		(28,457)
Tuition receivable, net	$	23,122	$	55,694

Schedule of allowance for doubtful accounts

The following table illustrates changes in the Company’s allowance for doubtful accounts for each of the three years ended December 31, 2018 (in thousands):


	2016		2017		2018
Allowance for doubtful accounts, beginning of period	$	10,024	$	10,201	$	12,687
Additions charged to expense		16,503		21,751		37,704
Additions from merger		—		—		6,601
Write-offs, net of recoveries		(16,326)		(19,265)		(28,535)
Allowance for doubtful accounts, end of period	$	10,201	$	12,687	$	28,457

Schedule of reconciliation of shares used to calculate basic and diluted earnings (loss) per share

Set forth below is a reconciliation of shares used to calculate basic and diluted earnings (loss) per share for each of the three years ended December 31, 2018 (in thousands):


	2016	2017	2018
Weighted average shares outstanding used to compute basic earnings per share	10,610	10,678	15,190
Incremental shares issuable upon the assumed exercise of stock options	5	39	—
Unvested restricted stock and restricted stock units	230	482	—
Shares used to compute diluted earnings (loss) per share	10,845	11,199	15,190