Stockholders' Equity - Narrative (Details) $ / shares in Units, $ in Thousands						12 Months Ended
	Dec. 31, 2023 USD ($) vote $ / shares shares	Dec. 04, 2023 shares	Jun. 20, 2023 shares	Mar. 21, 2023 USD ($)	Dec. 03, 2021 USD ($) $ / shares shares	Dec. 31, 2023 USD ($) vote $ / shares shares	Dec. 31, 2023 TWD ($)	Dec. 31, 2022 USD ($) $ / shares shares	Dec. 31, 2021 USD ($) $ / shares	Jan. 01, 2024 shares	Dec. 29, 2023 $ / shares	Jan. 01, 2023 shares	Oct. 16, 2018 shares	Oct. 30, 2015 shares
Class of Stock [Line Items]
Shares authorized (in shares)	50,000,000					50,000,000
Preferred stock, par value per share (in dollars per share) | $ / shares	$ 0.0001					$ 0.0001
Shares issued (in shares)	0					0
Shares outstanding (in shares)	0					0
Options granted term						10 years	10 years
Stock-based compensation cost not yet recognized, options | $	$ 700					$ 700
Accelerated cost | $								$ 8,200
Sale of stock, equity issuable, amount | $				$ 150,000
Proceeds from issuance of common stock | $						0		0	$ 35,000
Escrowed shares (in shares)					1,200,000
Share price (in dollars per share) | $ / shares					$ 12.50
Stock-based compensation cost | $					$ 5,400	$ 5,579		19,169	23,565
ATM Offering Agreement
Class of Stock [Line Items]
Sale of stock, equity distribution agreement, maximum offering (in shares)			13,266,011
Number of shares issued (in shares)	2,069,538
Issue price (in dollars per share) | $ / shares	$ 0.52					$ 0.52
Proceeds from issuance of common stock | $	$ 900
Sale of stock, equity distribution agreement, remaining shares available (in shares)	11,196,473
Cost of revenue, excluding depreciation and amortization
Class of Stock [Line Items]
Accelerated cost | $								2,300
Stock-based compensation cost | $						$ 870		3,028	2,788
Sales and marketing
Class of Stock [Line Items]
Accelerated cost | $								1,000
Stock-based compensation cost | $						960		3,026	4,829
General and administrative
Class of Stock [Line Items]
Accelerated cost | $								1,900
Stock-based compensation cost | $						3,911		9,251	15,052
Research and development
Class of Stock [Line Items]
Accelerated cost | $								3,000
Stock-based compensation cost | $						$ (162)		$ 3,864	$ 896
2015 Equity Incentive Plan
Class of Stock [Line Items]
Exchange ratio					0.306%
Award vesting period						4 years	4 years
2021 Equity Incentive Plan
Class of Stock [Line Items]
Number of shares available for future issuance (in shares)					31,206,550
Increase in number of shares reserved for issuance as percentage of total number of outstanding shares					5.00%
Stock options
Class of Stock [Line Items]
Weighted-average remaining requisite service period						1 year	1 year
Share-based compensation arrangement by share-based payment award, options, grants in period, weighted average grant date fair value (in dollars per share) | $ / shares						$ 0.61		$ 1.64	$ 1.23
Intrinsic value of stock options exercised							$ 0	$ 1,100	$ 13,800
Stock options | 2015 Equity Incentive Plan
Class of Stock [Line Items]
Number of shares available for grant (in shares)														16,895,765
Number of shares available for future issuance (in shares)													15,700,000
Share-based compensation arrangement by share-based payment award, number of shares authorized (in shares)					32,595,765
Restricted stock units
Class of Stock [Line Items]
Number of awards outstanding (in shares)	8,759,000					8,759,000		7,495,000
Restricted Stock
Class of Stock [Line Items]
Unrecognized compensation costs | $	$ 5,500					$ 5,500
Number of awards outstanding (in shares)	2,400,000					2,400,000
Class A Common Stock, $0.0001 par value per share
Class of Stock [Line Items]
Common stock, shares authorized (in shares)	700,000,000					700,000,000		700,000,000
Common stock, par value (in dollars per share) | $ / shares	$ 0.0001					$ 0.0001		$ 0.0001
Common shares, votes per share (in vote per share) | vote	1					1
Share price (in dollars per share) | $ / shares											$ 0.25
Class A Common Stock, $0.0001 par value per share | 2021 Equity Incentive Plan
Class of Stock [Line Items]
Common stock, number of additional shares authorized												6,977,162
Class A Common Stock, $0.0001 par value per share | 2021 Equity Incentive Plan | Subsequent Event
Class of Stock [Line Items]
Common stock, number of additional shares authorized										7,280,589
Class B Common Stock
Class of Stock [Line Items]
Common stock, shares authorized (in shares)	20,000,000					20,000,000		20,000,000
Common stock, par value (in dollars per share) | $ / shares	$ 0.0001					$ 0.0001		$ 0.0001
Common shares, votes per share (in vote per share) | vote	50					50
Number of shares transferred (in shares)		1,200,000
Class C Common Stock
Class of Stock [Line Items]
Common stock, shares authorized (in shares)	10,000,000					10,000,000		10,000,000
Common stock, par value (in dollars per share) | $ / shares	$ 0.0001					$ 0.0001		$ 0.0001
Common shares, votes per share (in vote per share) | vote	0					0