Net Income Per Share Attributable to Common Stockholders - Basic and Diluted Net Income per Share (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended						9 Months Ended
	Sep. 30, 2021	Jun. 30, 2021	Mar. 31, 2021	Sep. 30, 2020	Jun. 30, 2020	Mar. 31, 2020	Sep. 30, 2021	Sep. 30, 2020
Numerator:
Net income	$ 13,526	$ 9,921	$ 4,918	$ 6,231	$ 653	$ 904	$ 28,365	$ 7,788
Denominator:
Weighted average common shares outstanding – basic	50,559,636			10,335,359			49,754,449	10,178,598
Net income per share attributable to common stockholders – basic: (in usd per share)	$ 0.27			$ 0.12			$ 0.57	$ 0.10
Denominator:
Weighted average common shares outstanding – basic	50,559,636			10,335,359			49,754,449	10,178,598
Weighted average shares outstanding – diluted	56,498,891			15,876,890			56,575,867	14,072,248
Net income per share attributable to common stockholders – diluted (in usd per share)	$ 0.24			$ 0.10			$ 0.50	$ 0.09
Class A
Numerator:
Net income	$ 7,294			$ 0			$ 15,295	$ 0
Less: Undistributed earnings allocated to participating securities	0			0			0	0
Reallocation of net income attributable to common stockholders	(1,229)			0			(7,265)	0
Net income attributable to common stockholders – basic	$ 6,065			$ 0			$ 8,030	$ 0
Denominator:
Weighted average common shares outstanding – basic	22,669,223			0			14,087,401	0
Net income per share attributable to common stockholders – basic: (in usd per share)	$ 0.27			$ 0			$ 0.57	$ 0
Numerator:
Net income attributable to common stockholders - diluted	$ 5,445			$ 0			$ 7,146	$ 0
Denominator:
Weighted average common shares outstanding – basic	22,669,223			0			14,087,401	0
Options to purchase common stock (in shares)	0			0			85,726	0
Restricted stock (in shares)	11,553			0			23,222	0
Employee stock purchase plan shares (in shares)	63,068			0			58,715	0
Weighted average shares outstanding – diluted	22,743,844			0			14,255,064	0
Net income per share attributable to common stockholders – diluted (in usd per share)	$ 0.24			$ 0			$ 0.50	$ 0
Class B
Numerator:
Net income	$ 6,232			$ 6,231			$ 13,070	$ 7,788
Less: Undistributed earnings allocated to participating securities	0			(5,035)			0	(6,788)
Reallocation of net income attributable to common stockholders	1,229			0			7,265	0
Net income attributable to common stockholders – basic	$ 7,461			$ 1,196			$ 20,335	$ 1,000
Denominator:
Weighted average common shares outstanding – basic	27,890,413			10,335,359			35,667,048	10,178,598
Net income per share attributable to common stockholders – basic: (in usd per share)	$ 0.27			$ 0.12			$ 0.57	$ 0.10
Numerator:
Net income attributable to common stockholders - diluted	$ 8,081			$ 1,630			$ 21,219	$ 1,269
Denominator:
Weighted average common shares outstanding – basic	27,890,413			10,335,359			35,667,048	10,178,598
Options to purchase common stock (in shares)	5,864,634			5,541,531			6,653,755	3,893,650
Restricted stock (in shares)	0			0			0	0
Employee stock purchase plan shares (in shares)	0			0			0	0
Weighted average shares outstanding – diluted	33,755,047			15,876,890			42,320,803	14,072,248
Net income per share attributable to common stockholders – diluted (in usd per share)	$ 0.24			$ 0.10			$ 0.50	$ 0.09